synthetic roof underlayment vs felt

Breathable vs. Non-Breathable Underlayments: The Vapor Permeability War in Tropical Roofing

• September 14, 2026
• admin

When building or reroofing a sloped architectural shingle roof, attention naturally focuses on the visible outer surface: the color tone, the dimensional cut, and the wind rating of the shingles. However, building physicists know that the underlayment membrane directly beneath the shingles acts as the unsung structural shield of the entire roof envelope. The underlayment …