Modified bitumen roofing is a type of asphalt-based membrane designed to withstand weather and wear, but it can experience thermal movement, which is the expansion and contraction of the material due to temperature changes. This happens because roofs get very hot in the sun and cool down significantly at night or in colder weather. Over time, this constant movement can cause the membrane to develop wrinkles, cracks, or even splits, especially if the installation didn’t allow enough space for the material to expand or if the adhesive bond has weakened. Simple inspections you can do safely involve looking on the roof for bubbling or cracks, and checking the seams to see if they are lifting or separating. It’s best to perform these checks on a mild day when the roof is cool and dry to avoid slipping and further damage.
If you notice signs of thermal movement damage, it’s wise to contact a roofer promptly to avoid leaks and structural issues. When discussing repairs, ask whether they use flexible adhesives or details designed to accommodate thermal expansion, and how they plan to prevent the same problem from recurring. Also, inquire about the warranty coverage related to thermal movement issues, as some types of damage may not be covered if caused by improper installation or lack of maintenance. A reputable contractor will evaluate the entire roofing system, not just the visibly affected area, and provide a solution that balances durability, flexibility, and your budget. Keeping up with routine maintenance and timely repairs is the best way to protect your modified bitumen roof over its lifespan.