Infrared Roof and Moisture Scans
How Infrared Thermal Imaging Finds, Analyzes, and Prioritizes Moisture Issues in Roofing Materials
Infrared roof moisture surveying is often difficult for thermographers to understand because of the many variety of roofs they encounter. They must also have a working knowledge of roof waterproofing, roof insulation, roof decks, and roof substrates, and understand the thermodynamic characteristics for each. This may even vary depending on a variety of factors, including:
- Recent weather conditions
- Daily solar insulation
- Ambient conditions when survey is conducted
- Thermal conditions under the building roof
As a result, even though infrared thermography is the best means to conduct predictive maintenance on a roof, it is often performed incorrectly.
It’s good to keep in mind that even though there are numerous varieties of roofing systems, there is only one primary purpose of a roof – keep water out of the building it sits upon. While infrared thermography may be used to find water that works its way into a building, the focus of this page is to find moisture within flat and low-sloped roof systems.
How to Maintain Low-Sloped or Flat Insulated Roofs
Simply stated, a flat roof has no pitch or slope and utilizes a mechanical drain piping system to aid in the removal of water. A low-pitched roof has a slope of less than 3:12, and uses the same variety of draining system.
Roof assemblies may be either “warm” or “cold.” A warm roof is designed with all layers resting directly on one another. Without any room for ventilation, it is difficult to scan the roof from above. A cold roof is insulated below the roof deck, creating a ventilated space. This space keeps the deck and membrane near the outside temperature because there is much less heat transfer through the roof.
Maintenance for flat and low-sloped roofs is complicated and expensive. Thermographers ease this burden by finding moisture that is trapped inside the roofing system so that precise repairs can be made.
Entropy affects all things, and sooner or later every roof is going to wear out as it falls victim to wind, sun, rain, ice, snow, chemicals, and leakage. Recovering a roof costs between $2 and $3 per square foot, compared to $5 to $7 for replacement, so it makes sense to maximize the lifespan of the roof by conducting regular maintenance and repairs.
Understanding Waterproofing Problems on Low-Sloped Roofs
Roof waterproofing systems may fail by allowing leakage into the building or entrained moisture contamination. Leakage is self-explanatory, but it’s good to remember that the placement of a leak inside of a building rarely indicates the area where the roof is compromised. This is because the water will flow down the slope of the roof where it is eventually absorbed by the insulation materials.
This is why most leaks occur where the waterproofing is seamed, or where the roof has been penetrated. Thus, finding the exact spot of the leak may be tricky because it doesn’t manifest itself visibly until the insulation is completely absorbed.
Recovering and Re-roofing
Re-roofing requires that the existing roof be dismantled all the way down to the decking and then entirely replaced. Recovering a roof requires that the waterproofing layers be removed and then reapplied after wet insulation is replaced.
Infrared roof moisture surveys save owners money by pinpointing problem areas, allowing repair persons to replace only wet areas. The cost of these surveys is only around $.01 to $.10 per square foot, depending on the size of the roof, the number of anticipated issues, and how long the survey will take.
This is obviously far less money than recovering or re-roofing, so it’s a good idea to perform an infrared survey as part of a roof assessment management plan.