Home Inspection Thermal Imaging

A home inspection can incorporate a thermal imaging camera to accompany an electrical systems inspection. Components in electrical systems almost always overheat before they fail, problem areas are more easily and safely found when viewed through an IR (infrared) camera. Thermal imaging allows apparent temperatures to be seen as gradient colors, with hotter spots displayed as brighter colors, and cooler (and wet) spots displayed as darker colors. When a malfunctioning electrical component or connection is generating more heat than it should be, its apparent temperature will make it stand out when viewed through thermal imaging.

What kinds of problems can be detected?

During an inspection, electrical equipment, such as distribution panels, switch boards, contacts, transformers, receptacles, and service and control panels, can be examined through a thermal camera.  By viewing apparent temperature differences, home inspectors can identify and document problems, such as loose connections and overloaded circuits, which are the most common causes of electrical fires.  Other issues, such as transformer cooling problems, induced currents, arcing, and motor-winding faults, also become readily apparent.

Home Inspection Thermal Imaging

Thermal imaging can detect electrical issues that include:

  • excessively hot or loose connections;
  • overloaded wiring;
  • overloaded circuits;
  • overloaded transformers;
  • overloaded motors;
  • arcing; and
  • excessive harmonics.

Advantages of a Home Inspector Using an Thermal Camera for Electrical Inspections

Because viewing temperature differences through a thermal camera requires no physical contact, and can cover a lot of space in one sweep, no other technology allows electrical faults to be found as safely and as quickly as thermal imaging.  Another important benefit is that it allows problem areas and components to be located before damage from any serious failure or electrical fire occurs.  This helps ensure safety.  It can also save money that might otherwise need to spent on extensive repairs.

Here’s a list of advantages of using an thermal camera for electrical inspections during a home inspection:

  • It’s non-contact, which helps ensure a safe inspection.
  • It’s fast and accurate.
  • It helps identify problems before they cause serious failure or an electrical fire.
  • It’s non-intrusive, so there is no interruption of power during the inspection.
  • It can be used as part of inspections that are conducted as preventative maintenance.
  • It provides documentation of problems.

Home Inspection Tips

Before beginning the home inspection, it is useful to ensure that access is available to all areas and components that will be inspected.  The electrical systems can then be examined while operating under a normal load.  Any open panels or enclosures are typically inspected first.  A panel that shows signs of moisture, is heavily rusted, is buzzing or arcing, or that generally shows any signs of being unsafe should be reported but not opened or touched.  Infrared images can be taken from a safe distance for documentation.

Panels and other areas to be inspected that are deemed safe through visual inspection first, such as receptacles, can be examined by line of sight with the infrared camera.  It is quick and easy to view all components in most service panels with thermal imaging, and problem areas will be visible as apparent temperature differences.  These areas can then be documented by including an infrared image alongside a standard digital photo in the inspection report.  One practice that may be helpful is to document similar components operating under similar loads.  The side-by-side comparison of a properly functioning component and a similar one that is not operating correctly is a good way to gather additional details to present clear documentation without exceeding InterNACHI’s Standards of Practice for conducting a safe electrical inspection.

The thermal images taken are most useful when they are clear and in focus, allowing the most detail to be captured.  The same principles apply to standard, visible-light images taken at the same time for comparison.  These complementary images should be captured from the same angle and vantage point as the infrared images so that heat signatures detected by thermal imaging can be identified easily with the corresponding components in the visible-light or digital photo.
Infrared cameras that also incorporate the ability to switch over to standard digital photography are especially useful for electrical inspections because they allow for comparison without having to move or change position between photos.
When providing documentation after the home inspection, it is useful to include the following:
  • the exact locations of any problems found;
  • a description of the issue that also includes any nameplate data, and phase or circuit numbers;
  • copies of thermal images and corresponding visible-light or digital images;
  • any information regarding conditions that may affect the results, their repeatability, or the interpretation of the problem found.
Using a thermal camera for an electrical inspection during a home inspection is fast and safe, and is a great way to document problems that convey useful and easy-to-understand details for property owners.  Home buyers and home sellers will benefit from their home inspector utilizing this technology at their home inspection.
Electrical Red Flags:
  • Knob-and-tube wiring that is still live and working
  • Aluminum wiring
  • Evidence that the electrical has been modified
  • Service smaller than 100 amps, fuses for the branch circuits, or a breaker panel older than 40 years. Some older breaker panels have breakers that do not reliably do their intended job due to poor design or age. Some breaker panels deteriorate due to conditions such as dust or high humidity.
  • Wall switches that do not control anything. Sometimes fixtures are removed and wires are not capped off properly like they should be.
  • Lights in the house that flicker or dim and brighten. This could mean a damaged wire or loose connection.
  • Hidden junction boxes. The electrical code says that anytime wires are joined together in a junction box, that the junction box should be accessible and not hidden behind drywall.
  • Overloaded fuses of breakers
  • Outlets near water sources, outdoors, in garages and unfinished basements that are not GFCI (ground fault circuit interrupter) outlets. A GFCI receptacle will cut off power immediately if there is any leak of electricity out of the circuit.
  • Not enough outlets, or outlets that accept only two prong devices. These can lead to overloading of circuits.
Murfreesboro Mold Inspection

Mold Inspection Mold, Moisture and Your Home Inspection

Mold is variety of microscopic organisms that require a food source and moisture for growth. When both are present, mold grow quickly and keep producing.
Mold grows when there is too much moisture in your home. One of the most common reasons being that water is entering the house because something is failing. It could be the roof, exterior sheathing, windows and/or doors. Another reason could be that a lot of moisture is being produced inside the house, and there is not enough ventilation to get it out. If mold is seen anywhere in the house, you should ask yourself what might be causing it and how serious is the problem.
Discoloration is very often a sign of mold, but not all discoloration indicates mold. Chemical residues from cigarettes, candle soot, and outdoor pollution entering the house can be causes of discoloration that have nothing to do with mold.
Mold Inspection – Mold Basics
  • The key to mold control is moisture control.
  • If mold is a problem in your home, you should clean up the mold promptly and fix the water problem.
  • It is important to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth.

Mold Inspection – Why is mold in my home?

Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter, such as fallen leaves and dead trees. But indoors, mold growth should be avoided.  Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet.  There are many types of mold, and none of them will grow without water or moisture.
Common sources of excessive interior moisture are:
(1) air infiltration (moist outside air leaking in);
(2) poorly installed roofing or incorrectly flashed windows and doors;
(3) unsealed crawl spaces;
(4) improper surface drainage;
(5) inadequately vented bathrooms, kitchens, laundry appliances, water heaters, and furnaces; and
(6) leaking HVAC ducts.
Because the largest source of interior moisture comes from kitchens and bathrooms, one of the most cost effective, and easiest ways to reduce moisture is to install exhaust fans.
Mold Inspection – Can mold cause health problems?

Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing.  Molds have the potential to cause health problems.  Molds produce allergens (substances that can cause allergic reactions), irritants and, in some cases, potentially toxic substances (mycotoxins).  Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals.  Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis).  Allergic reactions to mold are common.  They can be immediate or delayed.  Molds can also cause asthma attacks in people with asthma who are allergic to mold.  In addition, mold exposure can irritate the eyes, skin, nose, throat and lungs of both mold-allergic and non-allergic people.  Symptoms other than the allergic and irritant types are not commonly reported as a result of inhaling mold.  Research on mold and health effects is ongoing.  This article provides a brief overview; it does not describe all potential health effects related to mold exposure.  For more detailed information, consult a health professional.  You may also wish to consult your state or local health department.

Mold Inspection – How do I get rid of mold? 

It is impossible to get rid of all mold and mold spores indoors.  Some mold spores will be found floating through the air and in house dust. Mold spores will not grow if moisture is not present.  Indoor mold growth can and should be prevented or controlled by controlling moisture indoors. If there is mold growth in your home, you must clean up the mold and fix the water problem. If you clean up the mold but don’t fix the water problem, then, most likely, the mold problem will recur.
Mold Inspection – Who should do the cleanup?
This depends on a number of factors.  One consideration is the size of the mold problem.  If the moldy area is less than about 10 square feet (less than roughly a 3-foot by 3-foot patch), in most cases, you can handle the job yourself, following the guidelines below.
  • If there has been a lot of water damage, and/or mold growth covers more than 10 square feet, consult with an InterNACHI inspector.
  • If you choose to hire a contractor (or other professional service provider) to do the cleanup, make sure the contractor has experience cleaning up mold.  Check references and ask the contractor to follow the recommendations of the EPA, the guidelines of the American Conference of Governmental Industrial Hygienists (ACGIH), or other guidelines from professional or government organizations.
  • Do not run the HVAC system if you know or suspect that it is contaminated with mold.  This could spread mold throughout the building.
  • If the water and/or mold damage was caused by sewage or other contaminated water, then call in a professional who has experience cleaning and fixing buildings damaged by contaminated water.
  • If you have health concerns, consult a health professional before starting cleanup.

Mold Inspection – Tips and Techniques

The tips and techniques presented in this section will help you clean up your mold problem.  Professional cleaners or re-mediators may use methods not covered here.  Please note that mold may cause staining and cosmetic damage.  It may not be possible to clean an item so that its original appearance is restored.

  • Fix plumbing leaks and other water problems as soon as possible. Dry all items completely.
  • Scrub mold off hard surfaces with detergent and water, and dry completely.
  • Absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy. Mold can grow on or fill in the empty spaces and crevices of porous materials, so the mold may be difficult or impossible to remove completely.
  • Avoid exposing yourself or others to mold.
  • Do not paint or caulk moldy surfaces.
  • Clean up the mold and dry the surfaces before painting. Paint applied over moldy surfaces is likely to peel.  If you are unsure about how to clean an item, or if the item is expensive or of sentimental value, you may wish to consult a specialist. Specialists in furniture repair and restoration, painting and art restoration and conservation, carpet and rug cleaning, water damage, and fire or water restoration are commonly listed in phone books. Be sure to ask for and check references. Look for specialists who are affiliated with professional organizations.
Mold Inspection – What to Wear When Cleaning Moldy Areas:
  • Avoid breathing in mold or mold spores.  In order to limit your exposure to airborne mold, you may want to wear an N-95 respirator, available at many hardware stores and from  companies that advertise on the Internet. (They cost about $12 to $25.)  Some N-95 respirators resemble a paper dust mask with a nozzle on the front, and others are made primarily of plastic or rubber and have removable cartridges that trap and prevent most of the mold spores from entering.  In order to be effective, the respirator or mask must fit properly, so carefully follow the instructions supplied with the respirator. Please note that the Occupational Safety and Health Administration (OSHA) requires that respirators fit properly (via fit testing) when used in an occupational setting.
  • Wear gloves. Long gloves that extend to the middle of the forearm are recommended.  When working with water and a mild detergent, ordinary household rubber gloves may be used.  If you are using a disinfectant, a biocide such as chlorine bleach, or a strong cleaning solution, you should select gloves made from natural rubber, neoprene, nitrile, polyurethane or PVC.  Avoid touching mold or moldy items with your bare hands.
  • Wear goggles. Goggles that do not have ventilation holes are recommended. Avoid getting mold or mold spores in your eyes.
Mold Inspection – How do I know when the remediation or cleanup is finished?

You must have completely fixed the water or moisture problem before the cleanup or remediation can be considered finished, based on the following guidelines:

  • You should have completed the mold removal.  Visible mold and moldy odors should not be present.  Please note that mold may cause staining and cosmetic damage.
  • You should have revisited the site(s) shortly after cleanup, and it should show no signs of water damage or mold growth.
  • People should have been able to occupy or re-occupy the area without health complaints or physical symptoms.
  • This is a judgment call; there is no easy answer. If you have concerns or questions, be sure to ask your InterNACHI inspector during your next scheduled inspection.
Mold Inspection – Moisture and Mold Prevention and Control Tips
  • Keep air-conditioning drip pans clean and the drain lines unobstructed and flowing properly.
  • Moisture control is the key to mold control, so when water leaks or spills occur indoors, ACT QUICKLY.  If wet or damp materials or areas are dried within 24 to 48 hours after a leak or spill happens, in most cases, mold will not grow.
  • Clean and repair roof gutters regularly.
  • Make sure the ground slopes away from the building’s foundation so that water does not enter or collect around the foundation.
  • Keep indoor humidity low.  If possible, keep indoor humidity below 60% relative humidity (ideally, between 30% to 50%).  Relative humidity can be measured with a moisture or humidity meter, which is a small, inexpensive instrument (from $10 to $50) that is available at many hardware stores.
  • If you see condensation or moisture collecting on windows, walls or pipes, ACT QUICKLY to dry the wet surface and reduce the moisture/water source.  Condensation can be a sign of high humidity.

Mold Inspection – Actions that will help to reduce humidity:

  • Vent appliances that produce moisture, such as clothes dryers, stoves, and kerosene heaters, to the outdoors, where possible.  (Combustion appliances, such as stoves and kerosene heaters, produce water vapor and will increase the humidity unless vented to the outside.)
  • Run the bathroom fan or open the window when showering.  Use exhaust fans or open windows whenever cooking, running the dishwasher or dish-washing, etc.
  • Use air conditioners and/or de-humidifiers when needed.

Mold Inspection – Actions that will help prevent condensation:

  • Reduce the humidity (see above).
  • Increase air temperature.
  • Increase ventilation and air movement by opening doors and/or windows, when practical.  Use fans as needed.
  • Cover cold surfaces, such as cold water pipes, with insulation.

mold inspection

Mold Inspection – Testing or Sampling for Mold

During a mold inspection, is sampling for mold needed?  In most cases, if visible mold growth is present, sampling is unnecessary.  Since no EPA or other federal limits have been set for mold or mold spores, sampling cannot be used to check a building’s compliance with federal mold standards.  Surface sampling may be useful to determine if an area has been adequately cleaned or remediated.  Sampling for mold should be conducted by professionals who have specific experience in designing  mold sampling protocols, sampling methods, and interpreting results.  Sample analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH), or other professional organizations.
Mold Inspection – Suspicion of Hidden Mold
During a mold inspection, you may suspect hidden mold if a building smells moldy but you cannot see the source, or if you know there has been water damage and residents are reporting health problems. During a mold inspection, mold may be hidden in places such as the backside of dry wall, wallpaper or paneling, the top-side of ceiling tiles, or the underside of carpets and pads, etc. During a mold inspection, other possible locations of hidden mold include areas inside walls around pipes (with leaking or condensing pipes), the surface of walls behind furniture (where condensation forms), inside ductwork, and in roof materials above ceiling tiles (due to roof leaks or insufficient insulation).
murfreesboro inspection
Mold Inspection (Hidden Mold Problems)
During a mold inspection, investigating hidden mold problems may be difficult and will require caution when the mold inspection involves disturbing potential sites of mold growth. For example, removal of wallpaper can lead to a massive release of spores if there is mold growing on the underside of the paper. If you believe that you may have a hidden mold problem, consider hiring an experienced professional.
Mold Inspection – Cleanup and Biocides
Biocides are substances that can destroy living organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup. There may be instances, however, when professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain, and these spores will not grow if the moisture problem has been resolved. If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine bleach with other cleaning solutions or detergents that contain ammonia because toxic fumes could be produced.
Surface mold should be washed with soap and water and allowed to dry thoroughly. There’s not need for bleaches to kill mold spores. After surface has dried, it should be painted with a stain killer. If mold has caused the drywall’s paper facing to roughen or delaminate, the drywall should be cut back at least 1ft beyond the damaged area and replaced.
If an home inspection reveals mold growing inside wall cavities, the affected area should be sealed off with sheet plastic. Damaged drywall should be cut back at least to the nearest stud center on both sides. Surface mold on framing should be scrubbed and allowed to dry before new drywall is installed.
Mold Inspection – Ten Things You Should Know About Mold Before A Mold Inspection
1.  Potential health effects and symptoms associated with mold exposure include allergic reactions, asthma, and other respiratory complaints.
2.  There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control        moisture.
3.  If mold is a problem in your home, you must clean up the mold and eliminate sources of moisture.
4.  Fix the source of the water problem or leak to prevent mold growth.
5.  Reduce indoor humidity (to 30% to 60%) to decrease mold growth by: a. venting bathrooms, dryers, and other moisture-generating sources to the outside; b. using air conditioners and de-humidifiers; c. increasing ventilation; and d. using exhaust fans whenever cooking, dish-washing, and cleaning.
6.  Clean and dry any damp or wet building materials and furnishings within 24 to 48 hours to prevent mold growth.
7.  Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent materials that are moldy (such as carpeting and ceiling tiles) may need to be replaced.
8.  Prevent condensation.  Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof and floors) by adding insulation.
9.  In areas where there is a perpetual moisture problem, do not install carpeting.
10.  Molds can be found almost anywhere; they can grow on virtually any substance, provided moisture is present. There are molds that can grow on wood, paper, carpet, and foods.
Prevention is the best solution for mold. Watch the house envelope for any signs of water penetration, and deal with them quickly. In high moisture areas such as bathrooms and kitchens, use products that will minimize the food source that lets mold grow, such as concrete board rather than drywall under any wall tiles. Plus, throughout your home, definitely in high moisture areas, make sure adequate ventilation is moving moisture out. Make sure bathroom vans are not venting out in the attic. They should be vented out to the exterior or at least to soffit vents at eave. Plus, check for standing water in the crawl space.
murfreesboro house desk inspection
House Deck Inspection: 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.  

Inspecting under a deck will be challenging if it is built close to the ground. As with porch framing, many codes allow the undersides of deck joists to be as low as 18″ above grade. Look for piers that are sunken or tilted, not fully supporting posts, posts that lean or could be moved by hand, and posts that lack steel framing connectors. Use a screwdriver to probe post ends for rot, and to probe under footings that you suspect are sitting only on the ground to see how deep they are. Note any wood to soil contact or insect infestation to wood framing. Bottoms of stairs or stair carriages should rest on footings at least 6″ to 8″ above grade. Often, they rest directly on the ground and are rotted. Note any wood connections that are pulling apart, such as stair treads to carriages, or joists to rim joists.
Deck Loads:
A house 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 in a house deck inspection.

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.
In a house deck inspection, 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. In a house deck inspection, 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. In a house deck inspection, 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. In a house deck inspection, 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. In a house deck inspection, 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. In a house deck inspection, 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. In a house deck inspection, lawn sprinkler systems that regularly keep the deck wet contribute to decay.  
The image above depicts a downspout contributing to post decay. In a house deck inspection, 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 a house deck inspection and so should be noted in the report.

The image above depicts a “pick test.” In a house deck inspection, 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 a house deck inspections is a visual-only inspection, 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 strength of lag bolts. Girders should bear directly on top of posts.
Notched post to beam attachment.
The image above depicts a girder properly resting on a notched post. Girders should bear directly on top of posts.
 Proper girder to post connection.
The image above depicts a girder properly resting on a post. Girders should bear directly on top of 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:
In a house deck inspection, the most common cause of a deck collapse is when a ledger 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. 
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 house deck inspections, 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”, during a house deck inspection.  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:
In a house deck inspection, 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.
house deck inspection
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:
In a house deck inspection, 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. In a house deck inspection, 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.
House Deck Inspection

House Deck Inspection

The three images directly above depict graspable handrails. Many deck handrails improperly consist of 2″x 6″ lumber or decking. In a house deck inspection, handrails should be graspable, continuous and smooth.
House Deck Inspection
The image above depicts the minimum distance between stair handrail posts.  Stair handrails should have posts at least every 5 feet.
House Deck Inspection
The image above depicts permitted spacing at stairs.  Larger spacing presents a child-safety issue.
Electrical Receptacle:
House Deck Inspection
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.
House Deck Inspection
The image above depicts a weatherproof receptacle cover.  The deck receptacle should have a weatherproof cover.
Deck Location:
House Deck Inspection
The image above depicts a deck located above a septic tank access. In a house deck inspection, decks should not be located where they might obstruct septic tank accesses, underground fuel storage tanks, well heads, or buried power lines.
House Deck Inspection
The image above depicts a deck obstructing a basement bedroom’s emergency egress window.  In a house deck inspection, 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.
Modern Materials
There have been great advances in decking materials, connectors, and fasteners. To solve the persistent problems of deck nails popping up and deck boards lifting, many builders now use special deck screws or hidden decking clips to prevent nail splits. Composite lumber made of recycled plastic and wood fiber is now widely used for decking, handrails, and trim. Composite decking is largely impervious to water and insect damage. Rubberized deck coatings are often used on wood framing decks to prevent moisture entry. Coated decks should be designed to drain freely. In new construction, a secondary drain is typically installed 2″ above the lowest adjacent surface to prevent deep flooding should the lower drain get blocked. Drains should be checked often for debris, especially if trees overhang. Minor cracks and openings can often be repaired by recoating. However, coating can obscure decay or moisture-related damage to the materials below, so it may be advisable to consult a qualified pest-control business if your home inspection suggests further damage.
Are You Buying a Home?
The process can be stressful. A home inspection is supposed to give you peace of mind. Although, depending on the findings, it may have the opposite effect. You will be asked to comprehend a lot of information over a short period of time.  Your inspection will entail a written home inspection report, including checklists and photos, and what the inspector tells you during the inspection. All of this combined with the seller’s disclosure and what you notice yourself can make the experience overwhelming. How can you make this experience easier?
Home inspectors are professionals, and if yours is a member of InterNACHI, then you can trust that he is among the most highly trained in the home inspection industry. Most of your inspection will be related to maintenance recommendations and minor defects. These are good to know about.

However, the issues of the most importance will fall into four categories:

  1. major defects, such as a structural failure;
  2. conditions that can lead to major defects, such as a roof leak;
  3. issues that may hinder your ability to finance, legally occupy, or insure the home if not fixed immediately; and
  4. safety hazards, such as a live, exposed buss bar in the electrical panel.
home inspection report electric

home inspection report

Anything in these categories should be addressed ASAP. Most of the time, a serious problem can be corrected inexpensively to protect both life and property.

Most sellers are honest and are often surprised to learn of defects uncovered during an inspection. It’s important to realize that a seller is under no obligation to repair everything mentioned in your home inspection report. Keep things in perspective, because no house is perfect.
And remember that home-ownership is both a joyful experience and an important responsibility, so be sure to call on your InterNACHI Certified Professional Inspector to help you devise an annual maintenance plan that will keep your family safe and your home in tip top condition for years to come.