Modified bitumen roofing is a durable, multi-layered system that often includes a base sheet and one or two layers of modified asphalt for waterproofing. Ice and water shield is a peel-and-stick membrane designed to provide an extra barrier against water infiltration, especially in vulnerable areas like eaves, valleys, and around roof penetrations. When used with modified bitumen, the ice and water shield acts as an additional layer to prevent leaks caused by ice dams and wind-driven rain. It is typically installed beneath the modified bitumen layers in low-slope areas or sections prone to snow buildup. This helps protect the roof deck from water backup and can significantly extend the roof’s lifespan.
To check if your roof would benefit from an ice and water shield, look for signs such as recurring leaks at valleys or near gutters during winter or after heavy rains. Safe DIY diagnostics include inspecting attic ceilings for water stains and checking edges where ice dams may form. If these signs appear, or if you live in a region with heavy snow or freeze-thaw cycles, it’s a good idea to consult a roofer. When calling a contractor, ask if they plan to use ice and water shield beneath the modified bitumen and where exactly it will be installed. Also, inquire how its presence might affect your roof’s warranty, ensuring the membrane is compatible and properly integrated with the rest of the roofing system.