by Nick Gromicko, CMI®, Founder, International Association of Certified Home Inspectors (InterNACHI)

Graphics by InterNACHI’s Lisaira Vega
More than 2 million decks are built and replaced each year in North America.  InterNACHI estimates that of the 45 million existing decks, only 40% are completely safe.
Deck inpection.
Because decks appear to be simple to build, many people do not realize that decks are, in fact, structures that need to be designed to adequately resist certain stresses. Like any other house or building, a deck must be designed to support the weight of people, snow loads, and objects.  A deck must be able to resist lateral and uplift loads that can act on the deck as a result of wind or seismic activity.  Deck stairs must be safe and handrails graspable.  And, finally, deck rails should be safe for children by having proper infill spacing.   
A deck failure is any failure of a deck that could lead to injury, including rail failure, or total deck collapse.  There is no international system that tracks deck failures, and each is treated as an isolated event, rather than a systemic problem.  Very few municipalities perform investigations into the cause of the failure, and the media are generally more concerned with injuries rather than on the causes of collapses.  Rail failure occurs much more frequently than total deck collapses; however, because rail failures are less dramatic than total collapses and normally don’t result in death, injuries from rail failures are rarely reported.  
Here are some interesting facts about deck failure:
  • More decks collapse in the summer than during the rest of the year combined.
  • Almost every deck collapse occurred while the decks were occupied or under a heavy snow load.
  • There is no correlation between deck failure and whether the deck was built with or without a building permit.
  • There is no correlation between deck failure and whether the deck was built by a homeowner or a professional contractor.
  • There is a slight correlation between deck failure and the age of the deck.
  • About 90% of deck collapses occurred as a result of the separation of the house and the deck ledger board, allowing the deck to swing away from the house.  It is very rare for deck floor joists to break mid-span.
  • Many more injuries are the result of rail failure, rather than complete deck collapse.
  • Deck stairs are notorious for lacking graspable handrails.
  • Many do-it-yourself homeowners, and even contractors, don’t believe that rail infill spacing codes apply to decks.

This document does not address specific building codes, balconies, lumber species, grade marks, decks made of plastics or composites, mold, or wood-destroying insects.

This document focuses on single-level residential and commercial wood decks.  Recommendations found within this document exceed the requirements of both InterNACHI’s Residential Standards of Practice and the International Standards of Practice for Inspecting Commercial Properties. 
A proper deck inspection relies heavily on the professional judgments of the inspector.  This document will help improve the accuracy of those judgments.

Required Deck Inspection Tools:

  • flashlight;
  • measuring tape;
  • ladder; 
  • level;
  • plumb bob;
  • probing tool; and
  • hammer.

Optional Inspection Tools:

  • moisture meter;
  • magnet; and
  • calculator.
Deck Loads:
A deck inspection should progress in much the same order as deck construction.  Inspectors should start at the bottom.  If a deck is deemed unsafe from underneath, the inspector should not walk out onto the deck to inspect decking, handrails, etc. The inspector should stop and report the safety issues.

The image above depicts an evenly distributed deck load.  Building codes require decks to be designed to carry a uniformly distributed load over the entire deck.  If evenly distributed, half of the load is carried by the deck-to-house connection, and the other half is carried by the posts.
The image above depicts a typical deck load distribution.  People tend to gather near the railings of a deck, and so more load is likely carried by the posts.
Hot tubs filled with water and people are heavy and can weigh a couple of tons. Most decks are designed for loads of 40 to 60 pounds per square foot. Hot tubs require framing that can support over 100 pounds per square foot.
Footings and Posts:
Required footing depths vary based on local building codes. The depth is normally below the frost line, or 12 inches (where frost lines are not applicable).

The above image depicts the 7-Foot Rule. On steep properties, the slope of the ground around the footing could affect the footing’s stability. The 7-Foot Rule states that there should be a least 7 feet between the bottom of a footing and daylight.
Posts in contact with soil should be pressure-treated and oriented so the cut end is above grade.
The image above depicts a free-standing deck (not attached to the home or building). A footing near a home must be on undisturbed soil.  Some codes consider soil to be “undisturbed” if it hasn’t been disturbed in more than five years.  It may be difficult to find undisturbed soil near the foundation of a new home.
Unattached post.
The image above depicts a post base that is not attached to its footing. Posts should be connected to their footings so that the posts don’t lift or slip off.

Pre-cast concrete pier.

The image above depicts a pre-cast concrete pier. Posts can lift out of pre-cast concrete piers, and piers can slide. Posts should be connected to their footings so that the posts don’t lift or slip off.

The image above depicts a proper post-to-footing connection.  Posts should be connected to their footings so that the posts don’t lift or slip off their footings.
The image above depicts an adjustable post-to-footing connection. Posts should be connected to their footings so that the posts don’t lift or slip off their footings.

The above image depicts a lawn sprinkler keeping a deck post wet.  Lawn sprinkler systems that regularly keep the deck wet contribute to decay.  
The image above depicts a downspout contributing to post decay.  Downspouts should not discharge near deck posts.
The image above depicts the indentation left over from the footing hole, causing a puddle.  Puddles contribute to post decay.
Wood can decay and degrade over time with exposure to the elements. Decay is a problem that worsens with time. Members within the deck frame that have decayed may no longer be able to perform the function for which they were installed. Paint can hide decay from an inspector and so should be noted in the report.

The image above depicts a “pick test.” The pick test uses an ice pick, awl or screwdriver to penetrate the wood surface. After penetrating the wood, the tool is leveraged to pry up a splinter, parallel to the grain, away from the surface. The appearance and sound of the action is used to detect decay. The inspector should first try the pick test in an area where the wood is known to be sound to determine a “control” for the rest of the inspection. Decayed wood will break directly over the tool with very few splinters, and less or almost no audible noise compared to sound wood. The pick test cannot detect decay far from the surface of the wood. 
The image above depicts a pick test on a deck post. Although deck inspections are visual-only inspections, inspectors may want to dig down around posts and perform pick tests just below grade level to look for decay.
The image above depicts a high deck being supported with 4″x 4″ posts.   Tall 4″x 4″ posts twist under load and 4″x 4″ posts, even when treated, decay below grade too quickly.  In all but the lowest of decks, deck posts should be at least 6″x 6″, and be no higher than 12 feet; 14 feet is acceptable if cross-bracing is used. 
Often, the bottoms of the stringer boards for deck stairs have been found to rest on soil, concrete block or rock, as opposed to resting on posts installed below the frost line.  Posts set on soil are subject to rot due to moisture.  Posts that are set in unsound footings may cause movement and make the deck above unstable.
Girders and Beams:
The image above depicts the minimum distance of untreated support members from grade. Untreated joists should be at least 18 inches away from the ground. Girders should be 12 inches away from the ground. However, in many situations, exceptions are made where the elevation of the home does not provide for these minimum distances and the climate is very dry. 

Girder-post connection.
The image above depicts a girder improperly relying on the sheer strength of lag bolts. Girders should bear directly on posts.
Notched post to beam attachment.
The image above depicts a girder properly resting on a notched post. Girders should bear directly on posts.
 Proper girder to post connection.
The image above depicts a girder properly resting on a post. Girders should bear directly on posts.
Girders supporting joist should not be supported by deck ledgers or band joists.
The image above depicts a butt joint improperly located within a girder span. Butt joints in a girder span are generally not permitted unless specially engineered. Butt joints typically must be located above posts.  

The image above depicts notches in a supporting beam. Notches must be less than one-quarter the depth of the member. On the tension and compression faces, the notch depth must be less than one-sixth of the member’s depth, and the notch length must be less than one-third of the member’s depth. Notches are not permitted in the middle third of spans, or on the tension face of members that are greater than 3½ inches thick.
Inspecting for beam sag. 
The image above depicts a level being used to check for beam sag. Even with a carpenter’s level, it can be difficult to see beam sag from the front. 
The image above depicts beam sag being eyed-up. Often it is easier to detect beam sag by eye than with a level by looking along the bottom edge of the beam.
Ledger Connection:
The most common cause of deck collapse is when a ledgers pulls away from the band joists of homes and buildings. 
The two most common ways to correctly attach a ledger to a structure are with lag screws or through-bolts. The installation of through-bolts requires access to the back-side of the rim joist which, in some cases, is not possible without significant removal of drywall within the structure.
Most building codes state that, where positive connections to the primary building structure cannot be verified during inspection, decks shall be self-supporting (free-standing).
Determining the exact required spacing for the ledger fasteners is based on many factors, including:
  • joist length;
  • type of fastener;
  • diameter of fastener;
  • sheathing thickness;
  • use of stacked washers;
  • type of wood species;
  • moisture content;
  • band joist integrity; and
  • deck loads… 
…and so is beyond the scope of a visual inspection.  However, the spacing of ledger fasteners is primarily determined by the length of the joists.  
InterNACHI’s ledger fastener spacing formula provides inspectors with a rule-of-thumb:
On-center spacing of ledger fasteners in inches = 100 ÷ joist length in feet.
A deck with substantially fewer ledger fasteners than that recommended by InterNACHI’s formula may be unsafe.

The image above shows the minimum distance of fasteners to the edges and ends of a ledger board. Lag screws or bolts should be staggered vertically, placed at least 2 inches from the bottom or top, and 5 inches from the ends of the ledger board. Some codes permit the lag screws or bolts to be as close as 2 inches from the ends of the ledger board; however, avoiding the very ends of the ledger boards minimizes splitting from load stress.
Through-bolts should be a minimum of ½-inch in diameter, and have washers at the bolt head and nut. Lag screws should also be a minimum of ½-inch in diameter and have washers.  Expansion and adhesive anchors should also have washers.
Deck ledgers should be of at least 2’x 8′ pressure-treated wood.
Ledger Board and Band Joist Contact:
The image above depicts washers being used as spacers between the ledger board and band joist, which is incorrect.
In some cases, the ledger board and band joist are intentionally kept separated by a stack of washers on the lag screw or bolts to allow water to run between the two boards. In other cases, there is insulation between the two boards. Even worse is when the siding or exterior finish system was not removed prior to the installation of the ledger board. Situations like this, where the ledger board and band joist are not in direct contact, significantly reduce the strength of the ledger connection to the structure and are not recommended by InterNACHI, unless the two members are sandwiching structural sheathing.
The image above depicts a ledger board and band joist sandwiching the structural sheathing (correct).
All through-bolts should have washers at the bolt head and nut. 
The image above depicts a hold-down tension device. The 2007 IRC Supplement requires hold-down tension devices at no less than two locations per deck. 
Codes in some areas outright forbid attaching a ledger board to an open-web floor truss.
The image above depicts a ledger board attached to a concrete wall. Caulking rather than flashing is used.
The image above depicts a ledger board attached to hollow masonry. When the ledger is attached to a hollow masonry wall, the cell should be grouted.
The image above depicts a ledger board improperly supported brick veneer. Ledger boards should not be supported by stone or brick veneer.
Ledger boards should not be attached directly (surface-mounted) to stucco or EIFS, either. Stucco and EIFS have to be cut back so that ledger boards can be attached directly to band joists; however, cut-back stucco and EIFS are difficult to flash and weather-proof.
Ledger board flashing.
The image above depicts both over and under ledger board flashing. The ledger board should always be flashed even when the home or building has a protective roof overhang.  
Aluminum flashing is commonly available but should not be used. Contact with pressure-treated wood or galvinized fasteners can lead to rapid corrosion of aluminum.
The image above depicts a deck ledger attached to an overhang.  Decks should not be attached to overhangs. 
The image above depicts proper framing around chimneys or bay windows that are up to 6 feet wide. Framing around chimneys or bay windows that are more than 6 feet wide requires additional posts.
Maximum cantilever.
The image above depicts a cantilevered deck.  Joists should be cantilevered no more than one-quarter of the joist length and three times the joist width (nominal depth). Both conditions must be true.
Maximum cantilever.
The image above depicts a joist cantilever in the front of the deck and girder cantilevers on both sides of deck posts. Joists should be cantilevered no more than one-quarter the joist length and three times the joist width (nominal depth). Girders can be cantilevered over their posts no more than on-quarter the girder length. 
There are three ways a joist can be attached to a ledger: 
The first is by resting the joist on a ledger strip. The image above depicts a joist properly resting on a 2″x 2″ ledger strip. 
Joist notched over ledger strip. 
The second is by notching over a ledger strip. The image above depicts a notched joist properly resting a 2″x 2″ ledger strip. 
The third is by hanging the joists with joist hangers. The image above depicts joists properly attached to a ledger by way of metal joist hangers. 
The image above depicts a joist cut too short. Joists may rest on 2″x 2″ ledgers like the one above (or in joist hangers), but joists must be cut long enough to reach the ledger or band joist that is supporting them. 
The image above depicts joists that are not fully resting in their joist hangers. Joists should be fully resting in their joist hangers. 
The image above depicts a deck with post-to-joist diagonal bracing. Decks greater than 6 feet above grade should have diagonal bracing from posts to girder, and from posts to joists.
The image above depicts a deck with post-to-girder diagonal bracing.  Decks greater than 6 feet above grade should have diagonal bracing from posts to girder, and from posts to joists.
Free-standing decks (not supported by the home or building) should have diagonal bracing on all sides.
The image above depicts underside diagonal bracing of a deck. Decks greater than 6 feet above grade that do not have diagonal decking should have diagonal bracing across the bottoms of the joists to keep the deck square. A deck that is not held square could permit the outer posts to lean to the right or left, parallel to the ledger board, and thus twist the ledger away from the home or building.
As wood ages, it is common for cracks to develop. Large cracks (longer than the depth of the member) or excessive cracking overall can weaken deck framing.  Toe-nailed connections are always at risk for splitting.  Splitting of lumber near connections should be noted by the inspector.
Connectors and Fasteners:
The inspector should note missing connectors or fasteners.  All lag screws and bolts should have washers.
The image above depicts a “hammer test.”  Depending on how the deck was built, vital connections may have degraded over time due to various factors.  Issues such as wobbly railings, loose stairs, and ledgers that appear to be pulling away from the adjacent structure are all causes for concern.  The tightness of fasteners should be checked.  If it is not possible to reach both sides of a bolt, it may be struck with a hammer. The ring will sound hollow with vibration if the fastener is loose.  The ring will sound solid if the connection is tight.  The hammer test is subjective, so the inspector should hammer-test bolts that can be confirmed as tight or loose, and compare the sounds of the rings to develop a control. 
Corrosion of Connectors and Fasteners:
All screws, bolts and nails should be hot-dipped galvanized, stainless steel, silicon bronze, copper, zinc-coated or corrosion-resistant.  Metal connectors and fasteners can corrode over time, especially if a product with insufficient corrosion-resistance was originally installed. Corrosion of a fastener affects both the fastener and the wood.  As the fastener corrodes, it causes the wood around it to deteriorate.  As the fastener becomes smaller, the void around it becomes larger.  Inspectors normally do not remove fasteners to check their quality or size, but if the inspector removes a fastener, s/he should make sure that removal doesn’t result in a safety issue.  Fasteners removed should be from areas that have the greatest exposure to weather. Some inspectors carry new fasteners to replace ones they remove at the inspection.   
Posts and Rails: 

Missing posts.

The image above shows a guardrail supported solely by balusters. Guardrails should be supported by posts every 6 feet.
The image above depicts a notched-deck guardrail post attachment.  This common notched-type of attachment is permitted by most codes, but could become unsafe, especially as the deck ages. Because of leverage, a 200-pound force pushing the deck’s guardrail outward causes a 1,700-pound force at the upper bolt attaching the post. It is difficult to attach deck guardrail posts in a manner that is strong enough without using deck guardrail post brackets.
Notched guardrail post.
The image above depicts a notched-deck guardrail post attachment. This notched-around-decking type of attachment is permitted by most codes, but could become unsafe, especially as the deck ages. Because of leverage, a 200-pound force pushing the deck’s guardrail outward causes a 1,700-pound force at the upper bolt attaching the post. It is difficult to attach deck guardrail posts in a manner that is strong enough without using deck guardrail post brackets.

The image above depicts a deck guardrail post properly attached with brackets. Because of leverage, a 200-pound force pushing the deck’s guardrail outward causes a 1,700-pound force at the upper bolt attaching the post. It is difficult to attach deck guardrail posts in a manner that is strong enough without using deck guardrail post brackets.
Level cut post and balusters.
The image above depicts a post and balusters cut level and not shedding water. The end-grain of vertical posts and balusters should not be cut level.
Angle cut post and balusters.
The image above depicts a post and balusters properly cut at angles to shed water. The end-grain of vertical posts and balusters should be cut at an angle.
Missing Guardrails:
Decks that are greater than 12 inches above adjacent areas should have guardrails around the edges. Some codes require guardrails only around the edges of decks 30 inches or higher.
Improper Guardrail Height:
Most residential codes require the top of the guardrail to be at least 36 inches from the deck surface. Most commercial code height is 42 inches. 
The image above depicts child-unsafe guardrail infill. Infill should not permit a 4-inch sphere to pass through.
The image above depicts horizontal balustrades. Ladder-type guardrail infill on high decks is prohibited by some local codes because they are easy for children to climb over. 
Decking overhang <= 6 inches.
The image above depicts deck framing near a chimney or bay window. The ends of decking boards near the chimney or bay window can extend unsupported up to 6 inches.
Improperly spaced decking.  
The above image depicts decking that is laid too tight. Decking should have 1/8-inch gaps between boards so that puddles don’t form.

The above image depicts decking that is properly spaced. Decking should have 1/8-inch gaps between boards so that puddles don’t form. 
The image above depicts decking that isn’t staggered properly. Decking should be staggered so that butt joints don’t land on the same joist side by side.
The image above depicts decking lengths.  Some are too short. Each segment of decking should bear on a minimum of four joists.
Decking should be attached to the floor joists and rim joist, especially in high-wind areas.
Decking Nail Pull-Out:
Inspectors should look for splitting in decking and nail pull-out. Aside from the structural issue, nails that have pulled out or screws that are not driven into the decking fully can cause injury to bare feet.
Deck stair stringer.
The image above depicts a deck stair stringer. Stair stringers shall be made of 2″x 12″ lumber at a minimum, and no less than 5 inches wide at any point.
The image above depicts deck stair stringers. Stringers should be no more than 36 inches apart.
Stair ledger strips.
The image above depicts ledger strips properly located under stair treads. Where solid stringers are used, stair treads should be supported with ledger strips (as depicted), mortised, or supported with metal brackets.
Open stair risers.
The image above depicts a set of stairs with open risers. Most deck stairs have open risers and are not safe for children. Risers may be open but should not allow the passage of a 4-inch diameter sphere.
Uniform riser height.
The image above depicts stair riser height. To minimize tripping, the maximum variation amongst riser heights (difference between the tallest and shortest risers) should be no more than 3/8-inch.
The bottom step of a stairway leading up to a deck is typically at a different height than the rest of the steps. This can present a trip hazard.
Steps with open risers can present a tripping hazard if a user catches his foot by stepping too far into the tread. To mitigate this hazard, the risers can be closed or the treads can be made deeper.
Deck Lighting:
Decks rarely have light sources that cover the entire stairways. Any unlit stairway is a safety issue.
Stair Handrails:
Stairs with four or more risers should have a handrail on at least one side. According to the International Standards of Practice for Inspecting Commercial Properties, ramps longer than 6 feet should have handrails on both sides.
Handrail height.
The image above depicts proper stair handrail height. Handrail height should be between 34 and 38 inches measured vertically from the sloped plane adjoining the tread nosing.
The image above depicts a stair handrail that is not graspable. Many deck handrails improperly consist of 2″x 6″ lumber or decking. Handrails should be graspable, continuous and smooth.
The images above show that handrail ends should be returned or terminate in newel posts.
The next three images depict graspable handrails:
Graspable handrail.

The three images directly above depict graspable handrails. Many deck handrails improperly consist of 2″x 6″ lumber or decking. Handrails should be graspable, continuous and smooth.
Minimum distance between handrail posts.
The image above depicts the minimum distance between stair handrail posts.  Stair handrails should have posts at least every 5 feet.
Stair child safety.
The image above depicts permitted spacing at stairs.  Larger spacing presents a child-safety issue.
Electrical Receptacle:
The image above depicts a deck with an electrical receptacle, but the receptacle does not have a weatherproof cover.  As of 2008, the National Electric Code requires at least one receptacle outlet on decks that are 20 square foot or larger.
Weatherproof receptacle cover.
The image above depicts a weatherproof receptacle cover.  The deck receptacle should have a weatherproof cover.
Deck Location:
Poor deck location.
The image above depicts a deck located above a septic tank access.  Decks should not be located where they might obstruct septic tank accesses, underground fuel storage tanks, well heads, or buried power lines.
Deck obstructing emergency egress.
The image above depicts a deck obstructing a basement bedroom’s emergency egress window.  Egress openings under decks and porches are acceptable, provided the escape path is at least 36 inches (914 mm) in height, and the path of egress is not obstructed by infill or lattice.
This article is from InterNACHI and can be found at

Welcome to the Homeowner’s February Newsletter!  Each month, you’ll find plenty of useful information for keeping your house in great condition so that you can enjoy it for years to come. Preserve your investment—and keep your family safe and healthy—by maintaining your home using the following tips.

Indoor Air Quality Issues

Indoor air quality is generally worse than most people believe, but there are things you can do about it.

Some Quick Facts:

  • Indoor air quality can be worse than that of outdoor air.
  • Problems can arise from moisture, insects, pets, appliances, radon, materials used in household products and furnishings, smoke, and other sources.
  • Effects range from minor annoyances to major health risks.
  • Remedies include ventilation, cleaning, moisture control, inspections, and following manufacturers’ directions when using appliances and products.

Many homes are built or remodeled more tightly, without regard to the factors that assure fresh and healthy indoor air circulation. Many homes today also contain furnishings, appliances and products that can affect indoor air quality.

Signs of indoor air quality problems include:

  • unusual and noticeable odors;
  • stale or stuffy air and a noticeable lack of air movement;
  • dirty or faulty central heating or air-conditioning equipment;
  • damaged flue pipes and chimneys;
  • unvented combustion air sources for fossil-fuel appliances;
  • excessive humidity;
  • the presence of molds and mildew;
  • adverse health reactions after remodeling, weatherizing, bringing in new furniture, using household and hobby products; and
  • feeling noticeably healthier outside.

Common Sources of Air Quality Problems
Poor indoor air quality can arise from many sources. At least some of the following contaminants can be found in almost any home:

  • moisture and biological pollutants, such as molds, mildew, dust mites, animal dander, and cockroaches;
  • high humidity levels, inadequate ventilation, and poorly maintained humidifiers and air conditioners;
  • combustion products, including carbon monoxide from unvented fossil-fuel space heaters, unvented gas stoves and ovens, and back-drafting from furnaces and water heaters;
  • formaldehyde from durable-press draperies and other textiles, particleboard products, such as cabinets and furniture framing, and adhesives used in composite wood furniture and upholstery;
  • radon, which is a radioactive gas from the soil and rock beneath and around the home’s foundation, groundwater wells, and some building materials;
  • household products, such as paints, solvents, air fresheners, hobby supplies, dry-cleaned clothing, aerosol sprays, adhesives, and fabric additives used in carpeting and furniture, which can release volatile organic compounds (VOCs);
  • asbestos, which is found in most homes more than 20 years old. Sources include deteriorating, damaged and disturbed pipe insulation, fire retardant, acoustical ceiling tiles, and floor tiles;
  • lead from lead-based paint dust, which is created when removing paint by sanding, scraping or burning;
  • particulates from dust and pollen, fireplaces, wood stoves, kerosene heaters, and unvented gas space heaters; and
  • tobacco smoke, which produces particulates, combustion products and formaldehyde.

Tips for Homeowners
•       Ask about formaldehyde content before buying furniture, cabinets and draperies.
•       Promptly clean and dry water-damaged carpet, or remove it altogether.
•       Vacuum regularly, especially if you have pets, and consider using area rugs instead of wall-to-wall carpeting. Rugs are easier to remove and clean, and the floor underneath can also be easily cleaned.
•       Eliminate unwanted moisture intrusion by checking for sources (such as holes and cracks in the basement and other areas, and leaks from appliances), and by using a dehumidifier.
•       Open windows and use fans to maintain fresh air with natural and mechanical air circulation.
•        Always open the flue damper before using the fireplace.  This will also prevent carbon-monoxide poisoning.
•       If your air conditioner has a water tray, empty and clean it often during the cooling season.
•       If you smoke, smoke outdoors and away from any windows and doors.
•       Use the range vent above your stove whenever you cook.
•       Use the bathroom vent whenever you use the bathroom.
•       Don’t leave vehicles or lawn care equipment running in your garage.  Make sure the door leading from the home to the garage has a door sweep to help keep out vapors.

Your InterNACHI inspector can recommend more ways to help you maintain healthy indoor air quality for you and your family.

Dryer Vent Maintenance & Safety

House fires caused by dryers are far more common than are generally believed.  According to the National Fire Protection Agency, fires caused by dryers in 2005 were responsible for approximately 13,775 house fires, 418 injuries, 15 deaths, and $196 million in property damage. Most of these incidents occur in residences and are the result of improper lint cleanup and maintenance. Fortunately, these fires are very easy to prevent.

Clothes dryers evaporate the water from wet clothing by blowing hot air past them while they tumble inside a spinning drum. Heat is provided by an electrical heating element or gas burner. Some heavy garment loads can contain more than a gallon of water that will become airborne water vapor and leave the dryer and home through an exhaust duct, more commonly known as the dryer vent.

A vent that exhausts damp air to the home’s exterior has a number of requirements:
•       It should be connected. The connection is usually behind the dryer but may it be under it. Look carefully to make sure it’s actually connected.
•       It should not be restricted. Dryer vents are often made from flexible plastic or metal duct, which may be easily kinked or crushed where they exit the dryer and enter the wall or floor. This is often a problem since dryers tend to be tucked away into small areas with little room to work. Vent hardware is available that is designed to turn 90 degrees in a limited space without restricting the flow of exhaust air.  Air flow restrictions are a potential fire hazard.
•       One of the reasons that restrictions pose a fire hazard is that, along with water vapor evaporated out of wet clothes, the exhaust stream carries lint – highly flammable particles of clothing made of cotton, wool and polyester. Lint can accumulate in an exhaust duct, reducing the dryer’s ability to expel heated water vapor, which then accumulates as heat energy within the machine. As the dryer overheats, a subsequent mechanical failure can trigger a spark, which can cause the lint trapped in the dryer vent to burst into flames. This condition can cause the whole house to catch fire.  Fires generally originate within the dryer but spread by escaping through the ventilation duct, incinerating trapped lint, and following its path into the home’s walls.

Problems & Tips
If your dryer vent terminates in the crawlspace or attic, it can deposit moisture there, which can encourage the growth of mold, wood decay, and other structural problems. The vent may also terminate just under the attic ventilators. This is also a defective installation. Make sure your dryer vent terminates at the exterior and away from any doors and windows so that damp, exhausted air won’t re-enter the home. Also, the end of the dryer vent should have a free-moving damper installed to keep out birds and other pests that like to build nests in this warm environment.  If you find a screen, this is a defective installation because a screen can block lint and other debris, causing it to accumulate and leading to a house fire.  If it’s safety accessible, make sure your dryer vent is unobstructed and that the damper works properly.

WDO & Pest Control

Wood-destroying organisms and other pests can cause serious problems in the wooden structural components of a house, and an infestation may go unnoticed until the damage is already extensive. Control measures include preventing insect entry by sealing holes and cracks, and hiring a professional to apply chemicals for remedial treatment.  The most commons types of destructive insects are termites and ants.

Subterranean termites are the most damaging insects of wood. Their presence is hard to notice, and damage usually is found before the termites are seen. You should take measures to prevent infestations, which may require hiring a pest-control service.
If you see the following signs in your house, you might have termites:
•       frass or sawdust-like droppings, which result from the termites’ tunneling activity;
•       dirt or mud-like tubes or trails on various parts of the home’s structure, such as wooden support members, plumbing pipes, etc.;
•       damaged wood members (such as window sills); and
•       swarming winged insects within the home, especially in the spring or fall.

Ants are among the most prevalent pests in households, restaurants, hospitals, offices, warehouses, and virtually all buildings where food and water can be found. While mostly harmless to humans, carpenter ants can cause considerable damage.
The following clues are evidence that your home is host to an ant infestation:
•       long trails of ants, perhaps numbering in the hundreds or thousands. Ants assemble in long trails along structural elements, such as wires and pipes, and frequently use them to enter and travel within a structure to their destination;
•       a few straggler ants, which are scouts in search of food and nesting sites;
•       holes or cracks in walls or the foundation, especially where pipes enter the building, and around windows and doors. These can provide entry points for ants and other insects.  The kitchen (where food is stored and prepared) is a particular problem area;
•       frass deposits, which result from the ants carving tunnels or galleries in the wood;
•       a distinctive rustling sound similar to the crinkling of cellophane. Ants are small but their nests are large enough to produce perceptible noise; and
•       nests in mulch and vegetation outdoors next to the foundation. Check under potted plants, patio blocks, stepping stones, in piles of rocks, lumber and firewood.

Other Pests
Snakes, spiders, bees and/or scorpions may be living in your crawlspace, and while they pose little structural danger to the house, they certainly can harm you. Rapid retreat there can be difficult, so if you’re in your crawlspace for any reason (storing items, looking for moisture intrusion or a water leak, etc.), be aware of your escape paths, and carry an extra flashlight in case the one you’re using suddenly stops working.

Your crawlspace is also the most likely area in the house where hantavirus may be found. This is partly due to the fact that rodents that carry the pathogen are attracted to areas that are undisturbed by humans. Also, crawlspaces are generally dark places that lack ultraviolet (UV) radiation, which can rapidly inactivate the virus. Exposure to hantavirus may lead to Hantavirus Cardiopulmonary Syndrome (HCS), characterized by headaches, fever, difficulty breathing and, often, death. There is no known cure, vaccine or treatment that specifically targets HCS. However, if the symptoms are recognized early, patients may benefit from oxygen therapy.

The Importance of a WDO Inspection
Regular inspections of your house are an important part of home maintenance. Inspecting for wood-destroying insects can alert you to possible infestations in the wooden structural components of your home—a serious problem that often goes undetected for a long time.

Schedule you home inspection with Red Horse Home Inspection.  Follow us on Facebook.


by Nick Gromicko, CMI®

A wood-burning stove (also known as a wood stove) is a heating appliance made from iron or steel that is capable of burning wood fuel. Unlike standard fireplaces, wood stoves are typically contained entirely within the living space, rather than inset in the wall.Photo courtesty of

Wood stoves come in many different sizes, each suited for a different purpose:

  • Small stoves are suitable in single rooms, seasonal cottages or small, energy efficient homes. These models can also be used for zone heating in large homes where supplemental heating is needed.
  • Medium-size stoves are appropriate for heating small houses or mid-size homes that are intended to be energy-efficient and as inexpensive as possible to maintain.
  • Large stoves are used in larger homes or older homes that leak air and are located in colder climate zones.

To ensure safe and efficient use of wood-burning stoves, inspectors can pass along the following tips to their clients:


  • burn coal. Coal burns significantly hotter than wood, posing a fire hazard;
  • burn materials that will emit toxic chemicals, such as wood that has been pressure-treated or painted, colored paper, gift wrap, plastic, plywood, particleboard, or questionable wood from furniture;
  • burn wet wood. Generally speaking, it takes six months for cut, stored wood to dry out and be ready for use in wood-burning stoves;
  • burn combustible liquids, such as kerosene, gasoline, alcohol or lighter fluid;
  • let small children play near a lit wood-burning stove. Unlike standard fireplaces, the sides of which are mostly inaccessible, all sides of wood stoves are exposed and capable of burning flesh or clothing; or
  • let the fire burn while the fire screen or door is open.


  • use a grate to hold the logs so that they remain secured in the stove and the air can circulate adequately to keep the fire burning hot;
  • keep the damper open while the stove is lit;
  • dispose of ashes outdoors in a water-filled, metal container;
  • check smoke alarms to make sure they are working properly; and
  • periodically remove the stovepipe between the stove and the chimney so that it can be inspected for creosote. Homeowners may want to hire a professional to perform this service.

Efficiency and Air PollutantsWood-burning stoves account for the smoke pictured in this photo taken in Chico, CA

While federal and state governments crack down on vehicle and industrial emissions, they do relatively little to limit the harmful air pollution emitted from wood stoves. The problem is so bad that, in many areas, such as Chico, Caifornia (pictured at right), the smoke from wood stoves is the largest single contributor to that city’s air pollution.  Smoke from wood stoves can cause a variety of health ailments, from asthma to cancer.

To mitigate these concerns, the EPA sets requirements for wood-stove emissions based on the design of the stove: 4.1 grams of smoke per hour (g/h) for catalytic stoves, and 7.5 g/h for non-catalytic stoves. Some state laws further restrict airborne particulates, and many new models emit as little as 1 g/h. These two approaches — catalytic and non-catalytic combustion — are described briefly as follows:

  • In catalytic stoves, the smoky exhaust passes through a coated, ceramic honeycomb that ignites particulates and smoke gasses. Catalysts degrade over time and must eventually be replaced, but they can last up to six seasons if the stove is used properly. Inadequate maintenance and the use of inappropriate fuel result in an early expiration of the catalyst. These stoves are typically more expensive than non-catalytic models, and they require more maintenance, although these challenges pay off through heightened efficiency.
  • Non-catalytic stoves lack a catalyst but have three characteristics that assist complete, clean combustion:  pre-heated combustion air introduced from above the fuel; firebox insulation; and a large baffle to create hotter, longer air flow in the firebox. The baffle will eventually need to be replaced as it deteriorates from combustion heat.

The following indicators hint that the fire in a wood-burning stove suffers from oxygen deprivation and incomplete combustion, which will increase the emission of particulates into the air:

  • It emits dark, smelly smoke. An efficient stove will produce little smoke.
  • There is a smoky odor in the house.
  • There is soot on the furniture.
  • The stove is burning at less than 300º F. A flue pipe-mounted thermometer should read between 300º F and 400º F.
  • The flames are dull and steady, rather than bright and lively.

To ensure efficiency, practice the following techniques:

  • Purchase a wood-burning stove listed by Underwriters Laboratories. Stoves tested by UL and other laboratories burn cleanly and efficiently.
  • Burn only dry wood. Wood that has a moisture content (MC) of less than 20% burns hotter and cleaner than freshly cut wood, which may contain half of its weight in water.
  • Burn hardwoods, such as oak, hickory and ash once the fire has started. Softwoods, such as pine, ignite quicker and are excellent fire starters.
  • Make sure the stove is properly sized for the space. Stoves that are too large for their area burn inefficiently.
  • Burn smaller wood rather than larger pieces. Smaller pieces of wood have a large surface area, which allows them to burn hotter and cleaner.
In summary, wood-burning stoves, if properly designed and used appropriately for the space, are efficient, clean ways to heat a home.  This article is from InterNACHI and can be found at

by Nick Gromicko, CMI® and Kenton Shepard

Temperature/pressure-relief or TPR valves are safety devices installed on water heating appliances, such as boilers and domestic water supply heaters. TPRs are designed to automatically release water in the event that pressure or temperature in the water tank exceeds safe levels.
If temperature sensors and safety devices such as TPRs malfunction, water in the system may become superheated (exceed the boiling point). Once the tank ruptures and water is exposed to the atmosphere, it will expand into steam almost instantly and occupy approximately 1,600 times its original volume. This process can propel a heating tank like a rocket through multiple floors, causing personal injury and extensive property damage.
Water-heating appliance explosions are rare due to the fact that they require a simultaneous combination of unusual conditions and failure of redundant safety components. These conditions only result from extreme negligence and the use of outdated or malfunctioning equipment.
The TPR valve will activate if either water temperature (measured in degrees Fahrenheit) or pressure (measured in pounds per square inch [PSI]) exceed safe levels. The valve should be connected to a discharge pipe (also called a drain line) that runs down the length of the water heater tank. This pipe is responsible for routing hot water released from the TPR to a proper discharge location.

It is critical that discharge pipes meet the following requirements, which can be found in InterNACHI’s Water Heater Discharge Piping mini-course, at A discharge pipe should: 
  1. be constructed of an approved material, such as CPVC, copper, polyethylene, galvanized steel, polypropylene, or stainless steel. PVC and other non-approved plastics should not be used since they can easily melt.
  2. not be smaller than the diameter of the outlet of the valve it serves (usually no smaller than 3/4″).
  3. not reduce in size from the valve to the air gap (point of discharge).
  4. be as short and as straight as possible so as to avoid undue stress on the valve.
  5. be installed so as to drain by flow of gravity.
  6. not be trapped, since standing water may become contaminated and backflow into the potable water.
  7. discharge to a floor drain, to an indirect waste receptor, or to the outdoors.
  8. not be directly connected to the drainage system to prevent backflow of potentially contaminating the potable water.
  9. discharge through a visible air gap in the same room as the water-heating appliance.
  10. be first piped to an indirect waste receptor such as a bucket through an air gap located in a heated area when discharging to the outdoors in areas subject to freezing, since freezing water could block the pipe.
  11. not terminate more than 6 inches (152 mm) above the floor or waste receptor.
  12. discharge in a manner that could not cause scalding.
  13. discharge in a manner that could not cause structural or property damage.
  14. discharge to a termination point that is readily observable by occupants, because discharge indicates that something is wrong, and to prevent unobserved termination capping.
  15. be piped independently of other equipment drains, water heater pans, or relief valve discharge piping to the point of discharge.
  16. not have valves anywhere.
  17. not have tee fittings.
  18. not have a threaded connection at the end of the pipe so as to avoid capping.
Leakage and Activation
A properly functioning TPR valve will eject a powerful jet of hot water from the discharge pipe when fully activated, not a gentle leak. A leaky TPR valve is an indication that it needs to be replaced. In the rare case that the TPR valve does activate, the homeowner should immediately shut off the water and contact a qualified plumber for assistance and repair.
Inspectors should recommend that homeowners test TPR valves monthly, although inspectors should never do this themselves. The inspector should demonstrate to the homeowner how the main water supply can be shut off, and explain that it can be located at the home’s main water supply valve, or at the water supply shut-off for the appliance on which the TPR is mounted.
TPR Data Plate Information
  • The pressure at which a TPR valve will activate is printed on a data plate located beneath the test lever. This amount should not exceed the working pressure limit marked on the data plate of the water-heating appliance it serves.
  • The BTU/HR rating marked on the water-heating appliance data plate should not exceed that of the TPR, which is marked on the TPR data plate.
  • TPR valves with missing data plates should be replaced.

Although a TPR valve might never become activated, it is an essential safety component on boilers and domestic water heaters. Guidelines concerning these valves and their discharge pipes reflect real hazards that every homeowner and home inspector should take seriously. This article is from InterNACHI and can be found at

by Nick Gromicko, CMI® and Kenton Shepard

Knob-and-tube (K&T) wiring was an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1940s. The system is considered obsolete and can be a safety hazard, although some of the fear associated with it is undeserved.

InterNACHI inspectors should always disclaim knob-and-tube wiring during their inspections.

Facts About Knob-and-Tube Wiring:Knob and Tube Wiring

  • It is not inherently dangerous. The dangers from this system arise from its age, improper modifications, and situations where building insulation envelops the wires.
  • It has no ground wire and thus cannot service any three-pronged appliances.
  • While it is considered obsolete, there is no code that requires its complete removal.
  • It is treated differently in different jurisdictions. In some areas, it must be removed at all accessible locations, while others don’t, but inspect it for safety reasons.
  • It is not permitted in any new construction.

How Knob-and-Tube Wiring Works:           

K&T wiring consists of insulated copper conductors passing through lumber framing drill-holes via protective porcelain insulating tubes. They are supported along their length by nailed-down porcelain knobs. Where wires enter a wiring device, such as a lamp or switch, or were pulled into a wall, they are protected by flexible cloth or rubber insulation called “loom.”

Advantages of Knob-and-Tube Wiring:

  • K&T wiring has a higher ampacity than wiring systems of the same gauge. The reason for this is that the hot and neutral wires are separated from one another, usually by 4 to 6 inches, which allows the wires to readily dissipate heat into free air.
  • K&T wires are less likely than Romex cables to be punctured by nails because K&T wires are held away from the framing.
  • The porcelain components have an almost unlimited lifespan.
  • The original installation of knob-and-tube wiring is often superior to that of modern Romex wiring. K&T wiring installation requires more skill to install than Romex and, for this reason, unskilled people rarely ever installed it.

Problems Associated with K&T Wiring:

  • Unsafe modifications are far more common with K&T wiring than they are with Romex and other modern wiring systems. Part of the reason for this is that K&T is so old that more opportunity has existed for improper modifications.
  • The insulation that envelopes the wiring is a fire hazard.
  • It tends to stretch and sag over time.
  • It lacks a grounding conductor. Grounding conductors reduce the chance of electrical fire and damage to sensitive equipment.
  • In older systems, wiring is insulated with varnish and fiber materials that are susceptible to deterioration.

Compared with modern wiring insulation, K&T wiring is less resistant to damage.  K&T wiring insulated with cambric and asbestos is not rated for moisture exposure. Older systems contained insulation with additives that may oxidize copper wire. Bending the wires may cause insulation to crack and peel away.

K&T wiring is often spliced with modern wiring incorrectly by amateurs. This is perhaps due to the ease by which K&T wiring is accessed.

Building Insulation:

K&T wiring is designed to dissipate heat into free air, and insulation will disturb this process. Insulation around K&T wires will cause heat to build up, and this creates a fire hazard. The 2008 National Electrical Code (NEC) requires that this wiring system not be covered by insulation. Specifically, it states that this wiring system should not be in…

hollow spaces of walls, ceilings and attics where such spaces are insulated by loose, rolled or foamed-in-place insulating material that envelops the conductors.

Local jurisdictions may or may not adopt the NEC’s requirement. The California Electrical Code, for instance, allows insulation to be in contact with knob-and-tube wiring, provided that certain conditions are met, such as, but not limited to, the following:

  • A licensed electrical contractor must certify that the system is safe.
  • The certification must be filed with the local building department.
  • Accessible areas where insulation covers the wiring must be posted with a warning sign. In some areas, this sign must be in Spanish and English.
  • The insulation must be non-combustible and non-conductive.
  • Normal requirements for insulation must be met.

Modifications:Knob and Tube Wiring on thermal insulation

When K&T wiring was first introduced, common household electrical appliances were limited to little more than toasters, tea kettles, coffee percolators and
clothes irons. The electrical requirements of mid- to late-20th century homes
could not have been foreseen during the late 18th century, a time during which electricity, to many, was seen as a passing fad. Existing K&T systems are notorious for modifications made in an attempt to match the increasing amperage loads required by televisions, refrigerators, and a plethora of other electric appliances. Many of these attempts were made by insufficiently trained handymen, rather than experienced electricians, whose work made the wiring system vulnerable to overloading.
  • Many homeowners adapted to the inadequate amperage of K&T wiring by installing fuses with resistances that were too high for the wiring. The result of this modification is that the fuses would not blow as often and the wiring would suffer heat damage due to excessive amperage loads.
  • It is not uncommon for inspectors to find connections wrapped with masking tape or Scotch tape instead of electrical tape.

K&T Wiring and Insurance:

Many insurance companies refuse to insure houses that have knob-and-tube wiring due to the risk of fire. Exceptions are sometimes made for houses where an electrical contractor has deemed the system to be safe.

Advice for those with K&T wiring:

  • Have the system evaluated by a qualified electrician. Only an expert can confirm that the system was installed and modified correctly.
  • Do not run an excessive amount of appliances in the home, as this can cause a fire.
  • Where the wiring is brittle or cracked, it should be replaced. Proper maintenance is crucial.
  • K&T wiring should not be used in kitchens, bathrooms, laundry rooms or outdoors. Wiring must be grounded in order to be used safely in these locations.
  • Rewiring a house can take weeks and cost thousands of dollars, but unsafe wiring can cause fires, complicate estate transactions, and make insurers skittish.
  • Homeowners should carefully consider their options before deciding whether to rewire their house.
  • The homeowner or an electrician should carefully remove any insulation that is found surrounding K&T wires.
  • Prospective home buyers should get an estimate of the cost of replacing K&T wiring. They can use this amount to negotiate a cheaper price for the house.

In summary, knob-and-tube wiring is likely to be a safety hazard due to improper modifications and the addition of building insulation. Inspectors need to be wary of this old system and be prepared to inform their clients about its potential dangers. This article is from InterNACHI and can be found at

by Nick Gromicko, CMI® and Ben Gromicko

Polyurethane spray foam is a versatile insulation material that is sprayed into building cavities where it quickly expands and molds itself to its surroundings. It is available in “closed-cell” and “open-cell” varieties, each of which offers advantages and disadvantages, depending on the requirements of its application. The following guide briefly explains the differences between these insulation options.Contractor installng spray foam insulation

Closed-Cell Polyurethane Foam

Closed-cell polyurethane foam (CCPF) is composed of tiny cells with solid, unbroken cell walls that resemble inflated balloons piled tightly together. The cells are inflated with a special gas selected to make the insulation value of the foam as high as possible. Like the inflated tires that hold up an automobile, the gas-filled bubbles, when dried, create a material that is strong enough to walk on without major distortion. Wall-racking strength can by enhanced when CCPF is applied, and its strength makes it preferable for roofing applications. The high thermal resistance of the gas gives CCPF an R-value of approximately R-7 to R-8 per inch, according to the U.S. Department of Energy (DOE), which is significantly better than its open-cell alternative. It also acts as a vapor barrier, making it the product of choice if the insulation is likely to be exposed to high levels of moisture. Its density is generally 2 lb/ft3 (32 kilograms per cubic meter [kg/m3]).

Over time, the R-value of CCPF can drop as some of the low-conductivity gas escapes and is replaced with ordinary air, a process known as thermal drift. Research performed by the DOE revealed that most thermal drift occurs within the first two years after the insulation material is applied, but then the foam remains relatively unchanged unless it is damaged.
Foam is a Fire Hazard
Semi-permeable rigid foam insulation and spray foam insulation (foam plastic) on the inside of basement foundation walls is often found during an inspection of the full-basement foundation of a house.  Its use could be a good strategy for a moisture-resistant finished basement. However, fire and smoke characteristics of this type of insulation require that it be covered with a fire-resistant layer, such as gypsum wallboard (drywall).
Sometimes this requirement works fine when the basement is being finished. This requirement of having spray foam insulation to be protected by a thermal barrier is found in the International Residential Code (IRC) 2015 Section R316. In most cases where spray polyurethane foam insulation is installed, the foam should be separated from the interior living spaces by an approved thermal barrier of at least 1/2-inch gypsum wallboard (drywall), 23/32-inch wood structural panel, or a material tested to meet the acceptable criteria from NFPA. There are a few exceptions to this requirement, including flame spread index ratings.
If a basement will only be insulated and not finished, a fire-rated foam panel or similar fire-rated covering needs to be used. Because the above-grade portions of the basement wall can dry to the outside, fire-rated insulation on these surfaces may be of an impermeable type. For example, it can have a foil facing.  But insulating approaches that restrict the drying potential of below-grade portions of the foundation wall toward the inside should be avoided.

In attics, a thermal barrier is not required when several conditions exist. Those conditions are listed within the IRC Code 2015 Section R316, and they include the attic access is required, the attic space is entered for only maintenance and when repairs are needed, and the foam insulation has been tested or the foam insulation is protected again ignition using a listed barrier material.

Packages and containers of spray foam insulation (or foam plastic) should be labeled and identified if they are delivered to a building site.

Open-Cell Polyurethane Foam

Open-cell polyurethane foam (OCPF) is a soft, flexible, spongy insulation with broken cell walls that permit air to fill them. They typically have a density of 0.5 lb/ft3 (8 kilograms per cubic meter [kg/m3]), which is significantly less than closed-cell insulation, as well as having a reduced R-value per inch, although OCPF still has excellent thermal-insulating and air-barrier properties. The foam is weaker and less rigid than closed-cell foams, too. It will require trimming and disposal of excess material as it expands to over 100 times its initial liquid size.

Builders often choose open-cell foam for the following advantages it affords, including:

  • its low cost. Where economical yield is important, open-cell foam is generally chosen over its more costly alternative;
  • providing a sound barrier. OCPF forms a more effective sound barrier in normal-frequency ranges than closed-cell foam. For this reason, OCPF is well-suited for installation beneath floors and around theater rooms;
  • its flexibility. Open-cell foam is more flexible than closed-cell foam, which allows it to adjust to weather-induced expansion and contraction of framing members. CCPF, by contrast, may develop hairline fractures because it cannot flex sufficiently; and
  • its permeability to moisture. While often cited as a reason to avoid the use of OCPF, in certain situations, it can be helpful for moisture to pass through insulation. Open-cell foam used in roofs, for instance, will allow a roof leak to make its way to the space below where it is more likely to be discovered. Closed-cell foam used in the same application would trap the moisture, hiding the leak and potentially leading to wood decay. In most situations, however, OCPF should not be used in any place where it might become wet, as moisture will diminish its insulative value. InterNACHI inspectors may call out open-cell insulation discovered in moist areas, such as in external applications or below grade.
In summary, polyurethane foam is available in two varieties that are suited for different applications.  This article is from InterNACHI and can be found at

by Nick Gromicko, CMI®

A pilot light is a small flame that is kept alight constantly in order to serve as an ignition source for a gas burner. They are used on many natural gas and propane appliances, such as water heaters, clothes dryers, central heating systems, fireplaces and stoves. Pilot lights are used as an ignition source for some fuel-burning appliances

The pilot light is fueled by a small amount of gas released from the gas pipe. When the appliance is turned on, a valve releases more gas, which is ignited by the pilot light. The light may need to be re-lit from time to time after being extinguished on purpose or by accident. Modern alternatives to the pilot light include a high-voltage electric arc between two electrodes placed close to the gas flow, and a red-hot surface made from silicon carbide, silicon nitride, or another material that can withstand prolonged heat exposure. While most commercial kitchens still rely on pilot lights for ovens and grills, their residential counterparts typically use electrical ignitions.


If a pilot light is accidentally extinguished, there exists a danger that the gas used to keep the flame lit will continue to vent, possibly into the living space. If this leak continues, its concentration may reach a point where a spark – such as that from a cigarette lighter, static electricity, or even the pilot light itself as it is re-lit – will cause a fire or even an explosion. As a precaution, the flow of gas to the pilot light is maintained by electrical circuitry that relies on the detection of the flame by a sensor.
Modern appliances that use pilot lights should be equipped with one or more of the following sensors types:
  • a photo-resistor, which detects the light emitted by the pilot light;
  • a thermometer, which detects the heat created by the pilot light; or
  • a voltmeter, which detects the electrical current created by the heat of the flame as it warms a thermocouple.  A thermocouple is a device that creates a voltage related to the temperature difference at the junction of two different metals.

Natural gas and propane can usually be detected by building occupants by their odor, which is added to these naturally odorless fuels specifically to alert people to a lurking danger. Numerous injuries have been reported, however, when homeowners have tried to re-light a pilot light after the appliance’s malfunctioning sensor failed to stop the flow of gas into the room. Thermocouples are degraded by continued exposure to the pilot light’s flame, which increases their electrical resistance and reduces their effectiveness as flame sensors. Periodic testing and replacement of these devices will mitigate the safety hazards posed by pilot light-equipped appliances.

While many inspectors and homeowners may not be aware of the danger, a number of houses are destroyed every year when a pilot light ignites the explosive gasses released from insecticide “bug bombs” and foggers. A fire erupted in a Newburgh, Ohio house after a man placed a roach fumigator under his kitchen sink and the fumes reached his oven’s pilot light. Even worse, when homeowners employ a recklessly large number of these foggers, they can generate enough gas to create a catastrophic explosion, and the determination of homeowners driven mad by cockroaches and fleas is occasionally enough incentive for them to employ such overkill. In one case, 19 foggers were Bug bombs were detonated by a pilot light, destroying this small San Diego homeunleashed in a 470-square foot San Diego home, filling the building with so much gas that the pilot light destroyed the home and launched shrapnel into the street. Fortunately, foggers are typically used in buildings that have been vacated. Three men were hospitalized, however, when an oven’s pilot light in a Thai restaurant in Perth, Australia ignited the gas released from 36 foggers – enough to blow the roof off the building in a massive explosion that rocked the suburban neighborhood, causing $500,000 in damages.

Energy Waste

Pilot lights are not needed for the majority of the time that they’re lit, which is how they waste a large amount of fuel. The exact amount of energy wasted depends on the unit, but various studies report that a pilot light burns $7.50 to $18 per month of natural gas, and even more for propane-fueled appliances. They waste more than 20% of the gas used in the United States, according to Cornell Environmental Health and Safety. A constantly burning pilot light also adds heat to the house, which might be useful in the winter, but adds to the heat load in the summer and places an unnecessarily greater burden on the air-conditioning system. Even in the winter, the appliance may be located in a utility room or other area that doesn’t require heating. Also, a typical pilot light can generate 450 pounds of carbon dioxide – a greenhouse gas — over a six-month period.

If an appliance isn’t needed for a long period of time, its pilot light may be extinguished to save energy, reduce greenhouse gas emissions, and reduce the risk of fire or explosion. Concerned homeowners can also purchase appliances equipped with the aforementioned alternatives to the pilot light. If they have any additional issues or concerns related to pilot lights or fuel-burning appliances, they should consult with an InterNACHI inspector during their next scheduled inspection.

In summary, pilot lights are a somewhat antiquated technology plagued by fears concerning fire and energy waste.  This article is from InterNACHI and can be found at

You can schedule you home inspection with Red Horse Home Inspection online.  Follow us on Facebook to see our newest post.

by Nick Gromicko, CMI® and Ethan Ward

What is a GFCI?

A ground-fault circuit interrupter, or GFCI, is a device used in electrical wiring to disconnect a circuit when unbalanced current is detected between an energized conductor and a neutral return conductor.  Such an imbalance is sometimes caused by current “leaking” through a person who is simultaneously in contact with a ground and an energized part of the circuit, which could result in lethal shock.  GFCIs are designed to provide protection in such a situation, unlike standard circuit breakers, which guard against overloads, short circuits and ground faults.
It is estimated that about 300 deaths by electrocution occur every year, so the use of GFCIs has been adopted in new construction, and recommended as an upgrade in older construction, in order to mitigate the possibility of injury or fatality from electric shock.


The first high-sensitivity system for detecting current leaking to ground was developed by Henri Rubin in 1955 for use in South African mines.  This cold-cathode system had a tripping sensitivity of 250 mA (milliamperes), and was soon followed by an upgraded design that allowed for adjustable trip-sensitivity from 12.5 to 17.5 mA.  The extremely rapid tripping after earth leakage-detection caused the circuit to de-energize before electric shock could drive a person’s heart into ventricular fibrillation, which is usually the specific cause of death attributed to electric shock.

Charles Dalziel first developed a transistorized version of the ground-fault circuit interrupter in 1961.  Through the 1970s, most GFCIs were of the circuit-breaker type.  This version of the GFCI was prone to frequent false trips due to poor alternating-current characteristics of 120-volt insulations.  Especially in circuits with long cable runs, current leaking along the conductors’ insulation could be high enough that breakers tended to trip at the slightest imbalance.
Since the early 1980s, ground-fault circuit interrupters have been built into outlet receptacles, and advances in design in both receptacle and breaker types have improved reliability while reducing instances of “false trips,” known as nuisance-tripping.

NEC Requirements for GFCIs

The National Electrical Code (NEC) has included recommendations and requirements for GFCIs in some form since 1968, when it first allowed for GFCIs as a method of protection for underwater swimming pool lights.  Throughout the 1970s, GFCI installation requirements were gradually added for 120-volt receptacles in areas prone to possible water contact, including bathrooms, garages, and any receptacles located outdoors.

The 1980s saw additional requirements implemented.  During this period, kitchens and basements were added as areas that were required to have GFCIs, as well as boat houses, commercial garages, and indoor pools and spas.  New requirements during the ’90s included crawlspaces, wet bars and rooftops.  Elevator machine rooms, car tops and pits were also included at this time.  In 1996, GFCIs were mandated for all temporary wiring for construction, remodeling, maintenance, repair, demolition and similar activities and, in 1999, the NEC extended GFCI requirements to carnivals, circuses and fairs.

The 2008 NEC contains additional updates relevant to GFCI use, as well as some exceptions for certain areas.  The 2008 language is presented here for reference.

2008 NEC on GFCIs

100.1 Definition

100.1  Definitions. Ground-Fault Circuit Interrupter. A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.

FPN: Class A ground-fault circuit interrupters trip when the current to ground has a value in the range of 4 mA to 6 mA.  For further information, see UL 943, standard for Ground-Fault Circuit Interrupters.

210.8(A)&(B)  Protection for Personnel

210.8 Ground-Fault Circuit Interrupter Protection for Personnel.

(A)  Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.

(1)   bathrooms;

(2)   garages, and also accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use;

Exception No. 1: Receptacles not readily accessible.

Exception No. 2: A single receptacle or a duplex receptacle for two appliances that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G)

(3)   outdoors;

Exception: Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow melting or deicing equipment shall be permitted to be installed in accordance with the applicable provisions of Article 426.

(4)   crawlspaces at or below grade level.

Exception No. 1: Receptacles that are not readily accessible.

Exception No. 2:  A single receptacle or a duplex receptacle for two appliances that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Exception No. 3: A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have ground-fault circuit interrupter protection.

Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G)

(6)   kitchens, where the receptacles are installed to serve the countertop surfaces;

(7)   wet bar sinks, where the receptacles are installed to serve the countertop surfaces and are located within 6 feet (1.8 m) of the outside edge of the wet bar sink;

(8)   boathouses;

(B) Other Than Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles Installed in the locations specified in (1), (2), and (3) shall have ground-fault circuit interrupter protection for personnel:

(1)   bathrooms;

(2)   rooftops;

Exception: Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or de-icing equipment shall be permitted to be installed in accordance with the applicable provisions of Article 426.

(3)   kitchens.

Testing Receptacle-Type GFCIs

Receptacle-type GFCIs are currently designed to allow for safe and easy testing that can be performed without any professional or technical knowledge of electricity.  GFCIs should be tested right after installation to make sure they are working properly and protecting the circuit.  They should also be tested once a month to make sure they are working properly and are providing protection from fatal shock.
To test the receptacle GFCI, first plug a nightlight or lamp into the outlet. The light should be on.  Then press the “TEST” button on the GFCI. The “RESET” button should pop out, and the light should turn off.
If the “RESET” button pops out but the light does not turn off, the GFCI has been improperly wired. Contact an electrician to correct the wiring errors.

If the “RESET” button does not pop out, the GFCI is defective and should be replaced.

If the GFCI is functioning properly and the lamp turns off, press the “RESET” button to restore power to the outlet.  This article if from InterNACHI and can be found at

by Nick Gromicko, CMI®

“A TV can be a child’s best friend, but it also can be a parent’s worst enemy,” says the mother of a 3-year-old who was crushed by a television, according to a 2009 Consumer Product Safety Commission (CPSC) study. The watchdog organization recently published an 18-year study on the dangers of furniture tip-overs, including startling findings that should be heeded by inspectors and parents alike.Dressers can easily tip over onto children
 Here are some facts and figures from the CPSC study:
  • From 1990 to 2007, an average of nearly 15,000 children under 18 visited emergency rooms each year for injuries received from furniture tip-overs. The number shows a 40% increase in injury reports over the duration of the study, hinting that the problem is growing worse. About 300 fatalities were reported.
  • Most injuries were to children 6 and under, and resulted from televisions tipping over.
  • The most severe injuries were head injuries and suffocation resulting from entrapment.
  • More than 25% of the injuries occurred when children pulled over or climbed on furniture.
  • Most of the injured children were males under 7 who suffered blows to the head.
  • The newer flat-screen TVs are not as front-heavy as the older, traditional TV sets, which means they may be less likely to tip over. Experts warn, however, that flat-screen TVs are still heavy to children, and they often have sharp, dangerous edges.
  • In 2006, Pier 1 Imports announced the recall 4,300 TV stands after one of them resulted in the death of a child in Canada.

The American Society for Testing and Materials (ASTM) has established standards for manufacturers which stipulate that dressers, chests of drawers and armoires should be able to remain upright when any doors or all drawers are open two-thirds of the way, or when one drawer or door is opened and 50 pounds of weight are applied to the front, simulating a climbing child. In addition, Underwriters Laboratories (UL) requires units to be able to remain upright when placed on a 10-degree angle with 70 pounds on top, to simulate the weight of a television. The ASTM and UL standards are voluntary, however, and many manufacturers will cut corners to save money. And despite efforts by the CPSC to enforce these standards, sub-standard furniture is still regularly sold at retail stores.

Parents can minimize the risks posed to their children from furniture tip-overs by practicing the following strategies:
  • Supervise young children at all times.
  • Place televisions low to the ground and near the back of their stands.
  • Strap televisions and furniture to the wall with heavy safety straps or L-brackets. Many of these devices do not require that any holes be drilled into furniture, and they can secure items up to 100 pounds.Safety Straps for furniture and TVs
  • Heavy items, such as televisions, should be placed far back on a dresser rather than at the front edge, which would shift the center of gravity forward and make the whole assembly more likely to tip over. Ideally, the center of gravity for furniture should be as low as possible, with the furniture placed back against a wall.
  • Only purchase furniture that has a solid base, wide legs, and otherwise feels stable.
  • Install drawer stops that prevent drawers from opening to their full extent, as a full extension can cause a dangerous forward-shift in the center of gravity.
  • Keep heavier items on lower shelves and in lower drawers.
  • Never place items that may be attractive to children, such as toys, candy or a remote control, on the top of a TV or piece of furniture.
  • Do not place heavy televisions on dressers or shelving units that were not designed to support such weight.
  • Place electrical cords out of the reach of children, and teach kids not to play with them. A cord can be used to inadvertently pull a TV, and perhaps its supporting shelf, onto a child.
  • Read the manufacturer’s instructions to learn about additional tips and hazards regarding the placement and use of your TV and furniture.
In summary, TVs and furniture can easily tip over and crush a small child if safety practices are not followed by parents. This article is from InterNACHI and can be found at
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by Nick Gromicko, CMI® and Kenton Shepard

Kickout flashing, also known as diverter flashing, is a special type of flashing that diverts rainwater away from the cladding and into the gutter. When installed properly, they provide excellent protection against the penetration of water into the building envelope.  
Several factors can lead to rainwater intrusion, but a missing kickout flashing, in particular, often results in concentrated areas of water accumulation and potentially severe damage to exterior walls. InterNACHI inspectors should make sure that kickouts are present where they are needed and that they are installed correctly. Water penetration into the cladding can occasionally be observed on the exterior wall in the form of vertical water stains, although inspectors should not rely on visual identification. There may be severe damage with little or no visible evidence.
Inspectors may observe the following problems associated with kickout flashing:
The kickout was never installed.
  • The need for kickout flashing developed fairly recently and the builder may not have been aware that one was required. The increased amount of insulation and building wrap that is used in modern construction makes buildings less breathable and more likely to sustain water damage. Kickout flashing prevents rainwater from being absorbed into the wall and is more essential than ever.
The following are locations where kickout flashing is critical:
  • anywhere a roof and exterior wall intersect, where the wall continues past the lower roof-edge and gutter. If a kickout flashing is absent in this location, large amounts of water may miss the gutter, penetrate the siding, and become trapped inside the wall; and
  • where gutters terminate at the side of a chimney.

The kickout was improperly installed.

  • The bottom seam of the flashing must be watertight. If it is not, water will leak through the seam and may penetrate the cladding.
  • The angle of the diverter should never be less than 110 degrees.

The kick-out was modified by the homeowner.

  • Homeowners who do not understand the importance of kickouts may choose to alter them because they are unsightly. A common way this is done is to shorten their height to less than the standard six inches (although some manufacturers permit four inches), which will greatly reduce their effectiveness. Kickout flashings should be the same height as the side wall flashings.
  • Homeowners may also make kickout flashings less conspicuous by cutting them flush with the wall.

    In summary, kickout flashing should be present and properly installed in order to direct rainwater away from the cladding.  This article if from InterNACHI and can be found at

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