Infrared Thermography Testing
Infrared Thermography (IR) is a non-invasive form of testing that seeks to identify areas where water/moisture becomes trapped in the roofing envelope. IR testing in the roofing/waterproofing industry works on the principle that dry insulating material builds and retains heat differently than wet insulating material. In other words, the heat signature of wet material within a roof assembly will have a different heat signature than that of dry material. An Infrared camera is used to survey the roof area and identify patterns that indicate moisture present within the assembly.
Unlike Electronic Leak Detection (ELD), infrared thermography does not identify breaches in the roofing/waterproofing membrane. However, it can be used as a quality assurance tool on new construction projects that have a roof system that does not support ELD. In addition, infrared thermography has been widely used as a means of identifying wet insulation before a roof replacement on an existing building, allowing the roofing contractor to more accurately budget for new insulation and salvage any undamaged existing insulation. Click the link below to find out if infrared thermography might add value to your next project.
Electrical Impedance (EI) operates on the principle that the electrical impedance of a material varies in proportion to its moisture content. The instrument used to conduct Electrical Impedance on low-sloped roofing and waterproofing assemblies is called a moisture meter. The moisture meter’s two conductive rubber electrodes mounted on the base are lightly pressed on the membrane being tested. The instrument nondestructively measures the electrical impedance of the substrate by creating a low frequency alternating electric field between the electrodes. The instrument reads moisture content from the surface of the membrane down into the insulation. Dry insulation creates greater impedance than wet insulation and provides different moisture content readings; the higher the reading the greater the potential moisture content.
Unlike infrared thermography and ELD where the entire roof area is tested, Electrical Impedance readings are taken in a predetermined grid pattern. It is also important to note that Electrical Impedance cannot locate breaches in the roofing/waterproofing membrane, nor can it be used on conductive membranes such as black EPDM.