Finding flat roof leaks
Many buildings, both commercial and residential, have flat or low sloped roofs. The roof coverings can be of many types.
- Tar and gravel
- Consisting of a concrete or wood roof deck over which layers of heavy felt roofing paper are built up and sealed using hot tar. A top layer of gravel is usually added to act as a sunscreen.
- "Torch down"
- A composition roofing material that comes in rolls and is applied in the long, overlapping strips. The backside of the material has an adhesive coating that is heated with a large propane torch to make it tacky so that it bonds to the surface it is being applied to as well as the adjacent strips of roofing.
- Membrane or diaphragm roof covering.
- This type of roof covering consists of a single layer of EPDM material that is "heat welded" together at the seams. This type of roof may or may not have ballast in the form of gravel or rocks added to the top to prevent lifting or "ballooning" due to wind pressure passing over the roof.
Finding leaks.
Finding leaks in a flat roof system can be difficult.
typically, physical inspection is performed to detect any obvious areas of concern such as unsealed roof penetrations by plumbing or other mechanical equipment, missing or damaged parapet flashings and physical damage or deterioration of the roof covering itself.
Usually, a leak will manifest itself as moisture intrusion on the interior finish surfaces. Unfortunately, there is often not a direct relationship between the location of the leak and where it shows up on the inside of the building. Water will obey the laws of gravity as well as take the path of least resistance and may travel many feet along structural components before dripping off onto the ceiling itself and alerting the occupant to a problem.
Barring the presence of any physically identifiable defects in the roof covering itself, finding the actual source of the leak can be quite difficult. The usual method of repair is to have the roofer reseal every possible leak source in the vicinity of the interior leak. Sometimes this is effective, often it's not. If the exact location of the leak cannot be identified, many roofers would just suggest a tear off and recover or just a recover of the entire roof. While this “shotgun” method may solve the problem, it's expensive, not very efficient and adds a lot of perfectly good roofing material to the landfill. Not very “Green”!
Thermal Infrared Scanning to the Rescue!
Due to a property called "thermal mass" saturated roof decks and insulation will absorb and hold more heat from the sun during the day than the dry areas of the roof. This heat can be detected as infrared radiation and quickly spotted by a specialized, high tech Thermal Imager like the FLIR B-CAM used by The Magic Leak Finders.
Roof surface during the daylight hours absorbs heat. The wet areas absorb more and hold it longer due to increased thermal mass of the wet materials.
At night, during a time of maximum heat difference between the cold sky and the warm roof deck, the wet areas will show up in the thermal imager as a “thermal hot-spot”.
The light yellow areas of this picture are the saturated areas of this roof system.
As the building owner, what does this mean for you?
By using a company like Thermal-Diagnostics & Magic Leak Finders to quickly identify the source of the leak, you could potentially save a significant amount of money by avoiding a complete roof replacement or recover when not necessary and only repair the areas that need it.
The cost difference can be significant. Compare the cost of a full roof replacement or recover at $3 to $5 per square foot to the cost of a Thermal Roof Scan and repair of the leaking areas only.
In the Los Angeles, Ventura & Orange County areas, contact
