Winter in Maine and with it comes many four-letter words such as “snow,” “high fuel bill,” and “dams.” By “dams,” I mean ice dams. Some winters are worse than others, causing boards and property managers to look for ways to reduce this serious problem in the coming months. Infrared scanning (thermography) can be one of the tools to combat ice dams and the related water damage they cause.
Ice dams primarily are caused by indoor heated air reaching the underside of the sloping roof sheathing, producing a cycle of melting/freezing snow creating an ice barrier at the drip edge of the roof. Further melting snow water will then back up from the dam and penetrate the roof surface under the shingles, leading to water infiltration and causing water damage to ceilings and wall surfaces. By the time this happens, snow roof raking rarely helps and chipping away at the ice dam often causes damage to the roof surface. Heating cables on the roof edge tend to reduce the life of shingles and do not address the reason the ice is forming in the first place.
Locate Air Leakage
Roof systems are designed to prevent the interior heated air from ever reaching the roof sheathing underside. Sometimes the soffit/ridge or other building venting system is poorly designed or installed. Sometimes the vents can be blocked by snow or ice. The fact that ice dams are developing provides sufficient empirical evidence the vent system is being overwhelmed with heated air from too much leakage of conditioned air into the attic space.
Infrared scanning and other energy audit techniques come into play when one is trying to determine where this heated air leakage is occurring and how much is happening. Today’s infrared camera scanning (or thermal imaging inspection, as it is often called) takes colored photographs (thermographs) of interior or exterior building surfaces. These colors represent a gradient in temperature interpreted by a skilled infrared imaging technician to locate air leaks or water leaks. The value of these images is directly related to the quality of the camera and the image interpretation accuracy of an experienced technician.
Detect Wet Surfaces
Using thermal imaging to resolve ice dam problems is just one way to use this amazing forensic tool, which deserves a spot in the building scientist’s arsenal of non-invasive inspection techniques. This imaging technology is not like X-rays; instead, thermography measures small surface temperature differentials by using infrared light waves. This can produce surprising results, such as locating mold or pest infestations.
Thermal imaging does not actually ‘see’ the mold but rather detects the small temperature difference between a wet and dry surface. It is well established that mold needs an environment with both food and moisture to spread. If a thermal scan of a condo unit reveals temperature surface differentials on a drywall ceiling or wall, further investigation could reveal a roof or plumbing leak. Sometimes, the multi-colored thermograph readings can even lead to the discovery of exterior siding gaps or missing/wet building envelope insulation.
Identify Repair Projects
Infrared scanning can also be used as a quality control tool for major condo repair projects. Thermal scans of electrical equipment can find overloaded wires and circuit breakers, as well as HVAC problems like leaking air duct seams and air-conditioner compressor piping. An infrared scan can reveal air leakage into the attic through misplaced insulation and air paths through ceiling light fixtures, plumbing, and electrical penetrations. These scans can also improve energy audits to ensure newer homes meet energy codes allowing less than 4 percent leakage. Homes upwards of five years old have been found on average to have leakage of 20 percent.
Thermal imaging is surprisingly cost effective. The scanning program can be limited to just one area in a unit or expanded to include the entire building, as discoveries are made. Most importantly, the field data can provide a very specific plan of repair based on hard evidence without any expensive invasive inspections or repairs. This specific information gleaned from thermal images can create a very limited scope of work to provide to a repair contractor, as compared to a job cost estimate with many unknowns, which may include inflated costs to cover risk and uncertainties.
Perhaps just as importantly, the thermal images allow both the board and unit owners to review hard evidence in making informed decisions when authorizing funding and necessary repairs. With knowledge comes confidence and peace of mind.
“Thermal Imaging Your Condo”
Article written by Jack Carr, P.E., R.S., LEED-AP, Criterium Engineers
Published in Condo Media February 2021 edition
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