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Commonly inspected components
• Walls
• Roofs
• Windows
• Doors
• HVAC
• Insulation
• Floor heating
Typical reasons for temperature hotspots or deviations
• Insulation verification like improperly installed or missing insulation
• Roof inspections; leaks cause water to enter to insulation
• Construction evaluation
• Locate air leakage
• Moisture intrusion; damage to insulation and building materials
• Mold detection
• Thermal bridging in joints between walls
• Heat loss through damaged seals in multi-plane windows
• Damaged heat ducts/leakage of buried steam lines
 Thermal Building Envelope Diagnostics
The primary diagnostic procedure for determining the thermal performance of a building envelope is infrared thermography. It can be used to identify heating and cooling loss due to poor construction, missing or inadequate insulation and moisture intrusion. Correcting the defects plays a significant role in increasing building efficiency and structural integrity.
Thermography can identify surface temperature variations of the building envelope, which relates to problems in the structure, thermal bridging, moisture content and air leakage.
Two primary mechanisms for heat loss in buildings are conduction through the walls and air leakage. Both can be identified from the surface of the building with infrared thermography. Early correction of the faults identified can be made before extensive damage occurs.
 Infrared Roofing Water Leak and Energy Efficiency
Flat roof membranes are the waterproof barriers between the outside elements and the interior of buildings. They come in a variety of materials and designs. They must be able to expand and contract, resist high winds and the effects of solar radiation and withstand foot traffic. It is easy to see why roofs leak.
Normally there is little or no water within a flat roof assembly. When a leak develops, water enters the assembly and, depending on the type of insulation system, is either absorbed by the insulation or runs to the cracks between the nonabsorbent insulation. When water enters the roof assembly it is there for a long time, sometimes the life of the roof.
Thermal capacitance is the physical property of a material's ability to store heat. The materials in roof assemblies have relatively low thermal capacitance, especially when compared to water. Water requires a lot of energy to raise its temperature and likewise must release a lot of energy to cool.
The physics used for thermal roof inspections is that dry roof insulation heats up and cools down faster than wet roof insulation. Infrared inspection goes beyond simply finding a leak by locating the extent of the moisture invasion of the insulation. To do this we require solar heating of a sunny day. Then at night, after the sun goes down and the roof surface begins to cool, the dry roof insulation cools faster than wet roof insulation.
Infrared inspections should be done under the right conditions to obtain the best infrared images. We require a different temperature between the day and night. For best results, here are some things to consider:
• Was it a clear sunny day?
• Is it a clear night (for good radiation cooling)?
• Is there little or no wind?
• Is the roof surface dry?
• Is the roof clear of snow, dirt and debris?
The type of insulation used on a roof will result in an infrared image that is characteristic of how that particular insulation absorbs water. Absorbent roof insulation acts similar to a sponge. The water migrates by capillary action throughout a complete roof board before it jumps to the adjacent board. This results in a checker board thermal pattern.
Nonabsorbent roof insulation creates a much different pattern when it becomes wet. The water is not absorbed and runs to the edge of the roof board. The water tends to collect at the edges of the boards resulting in a window frame pattern. Different patterns may result from other less common insulating systems.
There are many conditions that can produce thermal patterns that may look like they were created by wet insulation but are not, and others may mask the true condition of wet insulation. The ASTM specification C-1153 titled "Location of Wet Insulation in Roofing Systems Using Infrared Imaging" suggest performing verification of suspected wet insulation by core methods. The following are some examples of situations that may result in poor infrared inspections:
• Insulation with different R-values or different absorption characteristics which are commonly found in repaired areas
• Different internal building temperatures
• Extra gravel or bituminous left from construction
• Warm or cold air exhausting onto roof
• Re-radiation of heat from south or west facing walls
• Wind
• Internal sources of heat or cold such as lights, heaters, and steam pipes
• Dirt, vegetation and debris
• Walkway pads and buried steel plates
• Blisters
• Water ponding, steam plumes and water spray
During the winter use the same process; however, winter surveys are more difficult because the temperature differences are usually less than on summer surveys (5F vs. 20F). If the building is heated, the added heat flow from the building through wet insulation will help enhance the winter thermal patterns.
 Infrared Mold and Moisture Remediation
A key to prevention of mold growth.
Mold has existed in our environment long before the recent awareness of its presence in homes and businesses. The impact of mold on health is dependent upon the concentration of spores in the immediate area and the allergic effect on an individual. Potential health problems associated with mold exposure can take the form of allergic reactions or asthma. The problem is not limited to homes. Commercial buildings with moisture accumulation due to condensation or leaks are a candidate for mold growth. The mold topic has reached such proportions that congress has introduced a bill titled "United States Toxic Mold Safety and Protection Act of 2002" also know as the "Melina bill".
According to the U.S. Environmental Protection Agency, there is no practical way to eliminate mold spores in an indoor environment. The best way to control mold growth is to control moisture. Mold can begin growth in as little as 24 hours. Roof leaks and water pipe leaks are common sources of water accumulation that may cause mold growth. Mold has closed public schools and caused companies to spend millions of dollars on environmental tests and remediation. Clearly, there is more reason to become aware of roof conditions, before water begins dripping on a building owner's head.
Moisture present in roofs and walls can be detected with a sensitive infrared camera, under the right conditions. Infrared roof inspections are performed most effectively after sunset, when the roof gives off its heat energy accumulated during the day. The heat capacity of moisture soaked roof insulation is greater than that of dry insulation. As a result, the moisture soaked roof areas appear quite clearly when performing an infrared scan.
Similarly, it is possible to detect moisture located behind interior walls with an infrared camera, under the right conditions. The temperature difference created by the presence of moisture on the inside surface of a wall will appear differently than the surrounding area.
Infrared inspection is a fast, non-invasive method to discover moisture intrusion within the building envelope. Infrared inspection does not directly detect the presence of mold, rather it may be used to find moisture where mold may develop. The limitations to obtaining accurate infrared images pertain to the ability of the surface being scanned to emit heat energy. Gypsum (dry wall) in interior walls emits quite well, whereas highly reflective surfaces do not. Since the temperature difference between the wet and the dry wall are very slight, a sensitive infrared camera must be used.
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