Tab shingles are a common type of asphalt shingle that consists of flat pieces with cutouts (tabs) to give the roof a pattern. Thermal movement happens because roofs expand and contract with changes in temperature. This constant movement can cause tab shingles to lift, crack, or even curl over time, especially if the shingles were installed too tightly or if the roof deck is uneven. The cause usually lies in normal temperature swings combined with insufficient space for the shingles to expand or poor ventilation that traps heat and stresses the materials. These problems tend to appear as buckling tabs or gaps between shingles, and sometimes granule loss on the surface, which can indicate a shingle losing its protective layer.
To check for thermal movement damage yourself, look for shingles that seem raised or misshapen, especially after a hot day or cold night. Watch for rapid changes in these signs during the day, as that can be a clue. Make sure your attic has proper ventilation to reduce heat buildup, and check if shingles were installed with some allowance for expansion; tightly nailed shingles or those stuck too close can cause issues. If you notice widespread lifting or curling, it’s a good idea to call a professional roofer who can assess whether minor repairs or a new installation method is needed. When speaking with a contractor, ask how they allow for thermal movement when installing tab shingles and whether they recommend specific ventilation improvements that will help your roof last longer. Also, inquire if their work will be covered under a warranty that accounts for these kinds of shifting issues.