Felt Roofing vs Modern Flat Roof Systems

Felt roofing has been used on flat roofs for over a century. While it's still installed today, modern alternatives like EPDM, GRP, and single-ply membranes have significant performance advantages. Here's how they compare.

Traditional Felt Roofing

Traditional felt (bitumen) roofing is applied in multiple layers — usually three — and has been the standard flat roofing material for decades. Modern high-performance felt systems (SBS modified bitumen) are considerably better than basic torch-on felt.

• Pros: Familiar material, widely available, lower initial cost for basic systems
• Cons: Shorter lifespan (10–20 years), more maintenance required, less resistant to UV and temperature extremes

Modern Systems: EPDM, GRP, and Single-Ply

Modern flat roofing systems were developed to address the limitations of traditional felt. They offer longer lifespans, better UV and temperature resistance, and stronger manufacturer warranties.

• Pros: 25–50 year lifespan, better manufacturer warranties, lower long-term maintenance cost, better performance in extreme weather
• Cons: Higher initial cost, requires specialist installation knowledge

The Long-Term Cost Argument

While modern systems cost more upfront, the long-term economics strongly favour them. A felt roof replaced every 15 years will cost significantly more over 30 years than a single EPDM or GRP installation.

Our Recommendation

For any new flat roof installation, we recommend modern systems over traditional felt. The performance, durability, and warranty advantages make them the better investment for virtually all applications.