What composition of materials makes roll roofing impervious to moisture?

The composition of felt impregnated with asphalt or bitumen is what makes roll roofing impervious to moisture. This combination creates a waterproof barrier, which is essential for protecting structures from water infiltration.

The felt material serves as a substrate that provides durability and strength, while the asphalt or bitumen acts as a waterproofing agent. When these materials are combined, they form a cohesive layer that can withstand various weather conditions, preventing moisture from penetrating through the roofing system.

This combination is commonly used in low-slope roofing applications where traditional shingles may not be effective. The application process often involves rolling out large sheets of this material onto the roof surface and sealing the seams, ensuring a continuous waterproof covering.