A cant strip is a beveled strip installed at roof-to-wall transitions to ease membrane bends and improve waterproofing performance.

A cant strip is a triangular or beveled strip of material installed at the junction where a flat surface meets a vertical surface, most commonly at roof-to-wall or roof-to-parapet transitions. Its purpose is to soften the sharp angle, allowing roofing and waterproofing membranes to transition smoothly without cracking or stressing.

In roofing construction, cant strips are typically installed before base flashing or membrane application. They are commonly made from wood, fiberboard, lightweight concrete, or foam materials compatible with the roofing system. By reducing the angle at the transition, cant strips help extend the life of membranes and improve overall system performance.

Proper installation of cant strips is an important detail in durable roofing assemblies. Without a cant strip, membranes may crease or fatigue at sharp corners, increasing the risk of leaks. Roofing manufacturers and building codes often require cant strips at specific transitions to meet warranty and performance standards.

Cant strips are a small, inexpensive detail—but skipping them can drastically shorten the life of an entire roofing system.

• Furring Strip
• Index Strip
• Tack Strip