Why is Torch-on Roofing Often Recommended for High-rainfall Areas like the Lower Mainland?

Torch-on roofing (modified bitumen) is frequently recommended for high-rainfall areas like the Lower Mainland due to its proven performance in cool, damp coastal environments. This system offers several specific advantages for the region’s climate:

• Superior Waterproofing: The torch-applied, two-ply construction creates a robust, seamless application that effectively withstands Vancouver’s heavy rain and snow seasons.
• High Puncture Resistance: Torch-on membranes are reinforced with fiberglass or polyester mats, providing high durability against physical damage compared to other systems.
• Reliable Seams: In consistently moist conditions, seams that rely on adhesives may weaken. Torch-on systems use heat-applied installation to create reliable, welded bonds that are less likely to separate during wet winters.
• Proven Climate Suitability: Unlike some newer materials, modified bitumen is officially rated as "excellent" for its suitability in high-rainfall and cool climates like the Lower Mainland.

While the typical flat roof membrane lifespan for torch-on is 15 to 20 years, it remains a preferred choice for building owners who prioritize a durable, puncture-resistant barrier against persistent moisture.