Almost Like Seeing Inside Walls

Carl Brahe, Certified Home and Commercial Inspector

Technology now available to property inspectors allows a depth of inspection not possible before. Infrared thermography is providing a degree of information never before available to inspectors. Infrared (IR) cameras will become as important, and as basic, a tool as the flashlight for property inspectors. In the near future, inspectors without an IR camera will be as handicapped in their inspections as if they wore blindfolds.
While IR cameras can’t actually see inside walls, they can provide a lot of information about what can’t be seen with the naked eye. What IR cameras “see” is thermal energy or infrared light emanating from the surface of the wall. IR cameras make images using this light.

IR cameras used by inspectors are sensitive enough to image the heat left from your hand touching a wall. When you touch a wall, the heat from your finger raises the temperature of the wall. This difference in temperature lasts for a while and can be thermographed.

Temperature anomalies seen in buildings, or unexplained temperature differences in building materials, can reveal hidden defects. Different materials take on, hold and release heat at different rates. Using a handheld, IR camera with LED display, an inspector can “see” much that has been hidden in a building.

As temperatures change inside and outside, the temperature of building materials change. Temperatures change at a different rate in different materials. At any given moment, different materials in a building will be heating and cooling at different rates. This translates to varying temperatures between materials that is measurable on the surfaces of walls, floors, ceilings, roofs, appliances, electrical components, plumbing, etc.

Objects can be seen because of differences in temperature. Rebar in concrete may be clearly seen at the time of pouring the concrete. On a cold day, the rebar may be colder than the concrete and be displayed as dark objects. On a hot day, the rebar might be hotter than the concrete and be represented as bright objects. If rebar and concrete are exactly the same temperature, the rebar can no longer be seen. Typical IR cameras can detect a temperature difference of .18° F.
IR cameras are amazing tools that provide a way to drastically improve the quality and accuracy of building inspection and reporting. In my own house, I discovered that there was moisture inside the cathedral ceiling below two damaged shingles. In the photo below you can see the moisture and the location of the shingles. This was taken early in the morning in a time of cold weather. The next photo is the same ceiling taken with a conventional digital camera.

An IR image of a wall may be tuned so that dry wall screws are visible because of the difference in temperature between screws and drywall. The same image can be retuned, by changing the range of temperature imaged, to reveal the studs. Wood holds and releases heat at a different rate than metal screws, or drywall, insulation, plumbing and heating ducts. The temperature range and span of the image can be adjusted to highlight any of these materials even after the image has been stored and is being added to a report.
Things that inspectors can now “see’ with IR imaging can add more value to inspections and reporting than any other single tool. While we can’t actually see inside walls, floors, ceilings and roofs, we can see differences in surface temperatures caused by rodents, insects, mold, moisture and structural defects. Living things like mice and mold give off heat that may change the surface temperature of building components enough to be detected. Moisture cools and heats more slowly than building materials it may saturate and will be seen as a lighter, or darker, area. Missing or damaged insulation will cause variations in a walls surface temperature that can be detected by the IR camera.

Roof leaks can be very hard to find. Water appearing in an interior wall can originate at a flashing defect at the other end of the building. Repair can become trial and error until some measure works. Hopefully, the defect is discovered before resorting to replacing the entire roof out of sheer frustration. In the past, a person often had only several conflicting best guesses to guide them in finding a solution before too much damage to their health, home and finances occurred. Almost half of all roof defects result from poor workmanship and can be well hidden. Now tricky leaks can be traced to the real source in minutes by following the trail of temperature difference caused by water. The same applies to interior plumbing leaks and leaks behind siding.
EFIS, or synthetic stucco, has a history of mold problems due to leaks and improper installation. These problems can be impossible to diagnose without removing the siding or using IR thermography. Water that has soaked into the siding and become trapped might be seen clearly without using destructive means or guessing.

IR imaging provides the easiest, most accurate method for locating mold in building structure. Mold requires a certain level of sustained moisture and something to eat to survive. Wet building materials provide both. Wet building materials heat up and cool down much faster and slower than dry materials. This gives a contrast between wet materials and dry that can be photographed. Mold itself generates heat that may be detected.

Defects in electrical circuits and components are probably the most common fire hazards found in residential and commercial buildings. Overheating caused by corrosion, poor workmanship and defective materials can be difficult to locate. Finding these defects can be beyond the scope of most inspections. IR imagery shows hot wiring and electrical components identifying much that would otherwise be undiscovered


IR imaging can provide a map for energy savings. An IR camera can photograph heat, or cold, moving through a building. Air leaks in doors walls, ceilings, floors and fixtures can be visible. Insulation inside walls, floors and ceilings with can be evaluated.

While what can be revealed with IR is amazing, it is not x-ray vision and does have limitations. Images are made from differences in surface temperatures. All temperature differences in external walls can be wiped out by rain. Under the right conditions, leaks are clearly visible in flat roofs, but moisture under a roof deck can’t be detected from outside when it’s wet or snow covered. IR cannot penetrate some materials, like glass where only the reflected temperature seen. Sunshine can hide defects visible from either side of a wall that are clearly visible at night. Moisture in exterior walls may not be visible until the water is heated by sunshine in other cases. The quality of results depends on environmental factors and human interpretation.

IR imaging will become a requirement of all commercial and residential property inspectors very soon. The uses for IR imagery in inspections are only beginning to be explored. Inspection Perfection Inc offers IR imaging. We offer a full range of IR inspections as well as using it where appropriate in all regular inspections.

Types of IR Thermography Inspections.
• Energy Loss
• Electrical
• HVAC and Duct Work
• Moisture
• Mold
• Roof Leaks
• Plumbing Leaks
• Structural



Inspection Perfection, Inc - 303 573 5073
www.inspection-perfection.com
info@inspection-perfection.com