Freeze-Thaw Damage on Flat or Low-Slope Roofs
In several parts of the U.S., spring’s repeated cycle of freezing and thawing contributes to the wear and tear of facilities, especially the roof.
How Does Freeze-Thaw Affect a Roof?
Temperature swings can freeze, thaw, and refreeze water on the roof multiple times. Water can find its way within the roof membrane and this water will expand as it freezes. This creates a bigger opening in the membrane and allows even more water in during the next thaw. This cycle repeats over and over again until the damage becomes apparent.
The roof membrane can become brittle and crack. Existing penetrations can grow larger and allow more water in, resulting in more roof leaks.
Roof Elongation and Freeze-Thaw
The main factor of freeze-thaw effects on a flat roof is elongation. Elongation is how far a roof membrane will stretch or move, similar to a rubber band.
When selecting a new roof system or restoring an existing roof, be sure to ask about the elongation properties. Elongation is reported in a percentage. The greater the elongation, the more movement the roof will accommodate.
Preventing Roof Damage from Freeze-Thaw Cycles
While we can’t control the weather, there are ways to control its effects on your facility’s roof.
- If possible, start with a roof membrane with high elongation.
- Perform bi-annual inspections and preventative maintenance to identify existing penetrations water might enter. Resolving these issues before water gets in and freezes will significantly reduce the risk of leaks.
