Monday, February 10, 2014
During a home inspection, roof leaks are typically discovered by my direct observations and then confirmed by utilizing moisture meters on the sheathing below. But if I detect a moist area and the roof sheathing is not visible from below (such as a finished cathedral ceiling or a ceiling below a living area) the exact area of the leak can not be determined. Most homeowners have the misconception that moisture stains are caused from leaks that are directly above a wet area. It’s just not true in most situations. On gable roofs, some leaks occur at the ridge line area and cling to the rafters for quite a distance until it finally drips onto the ceiling below. In order for anyone to locate the exact area of the leak, the damaged ceiling must first be removed. This removal is necessary in order to “visualize” the exact intrusion point at the underside of the roof sheathing. Now before any of the ceilings can be removed, all the furniture must be removed from below the affected area. Then the floor must be protected from the falling debris and possibly requiring a scaffold system. All of this can cost hundreds and even thousands of dollars! Infrared Thermography is an invaluable non-destructive and non-contact tool that can detect and pinpoint hidden roof leaks without even damaging the interior or exterior surfaces. Then once I pinpoint the problem area, minimum surface areas can be removed in order to make the necessary repairs.
I prefer to perform all exterior roof inspections in the early evening hours. In order to perform the infrared inspection correctly, I require solar heating of a hot sunny day to heat up the roof surface. Then in the early evening (after the sun goes down), the roof starts to cool allowing my infrared camera to be able to detect obvious thermal differences if there are any moisture intrusions within the roof surface. Thermal properties of water are very unique (high thermal capacity), allowing water to be thermally observed on the surface and on the underside of roofing materials. If water is actively seeping into the cavity of a roof surface, the dry roof insulation will cool much faster than the soggy wet roof insulation, making it possible for me to observe the thermal differences.