Flat Roofing

Flat roof services

What is a hot bitumen roof?

Hot melt roofing systems are manufactured from a combination of refined bitumen, synthetic rubbers, fillers and other additives. This gives the finished monolithic membrane long lasting waterproofing integrity ideal for most new build flat roof applications and replacements with suitable protection layer.

Source: Iko group

Felt flat roofing remains a popular choice in the UK for extensions, garages, and outbuildings due to its affordability and adaptability. This layered bitumen-based system balances cost-effectiveness with functional weatherproofing, though it comes with trade-offs in longevity and maintenance. Below, we explore its components, benefits, drawbacks, and alternatives to help you make an informed decision.

Understanding Felt Flat Roofing

Felt roofing consists of 2–3 layers of bitumen-impregnated membranes (often reinforced with polyester or fibreglass) bonded to a flat roof deck. Modern systems typically use torch-on application, where heat fuses layers to create a waterproof seal. Key components include:

• Base layer: A vapor-control membrane to prevent condensation.

• Reinforced underlay: Adds structural strength.

• Mineral cap sheet: Provides UV resistance and aesthetic finish.

  
  

Advantages of Felt Roofing

1. Cost-Effective

   • Initial installation costs (£30–£60/m²) are lower than alternatives like EPDM or fibreglass.

   • Repairs are affordable, often requiring only patches and sealant.

     
     

2. Quick Installation

   • Torch-on systems can be installed in a day by professionals, reducing labour costs.

   • Self-adhesive variants suit DIY projects for sheds or small garages.

     
     

3. Versatility

   • Adapts to complex roof shapes and integrates with features like skylights.

   • Available in multiple colours (e.g., grey, green) for aesthetic flexibility.

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4. Durability

   • Properly installed systems last 15–25 years, with high-quality options reaching 30 years.

   • Resists wind uplift and minor impacts.

     
     

Disadvantages to Consider

1. Shorter Lifespan

   • Traditional felt lasts 15 to 25 years, compared to 30+ years for EPDM or fibreglass (which also have pros and cons).

   • UV exposure degrades bitumen over time, leading to cracks and brittleness.

     
     

2. Maintenance Demands

   • Prone to ponding water if drainage is inadequate.

   • Requires bi-annual inspections to detect splits or loose seams.

     
     

3. Weather Sensitivity

   • Extreme heat softens felt, risking warping; cold makes it brittle.

   • Torch-on installation poses fire risks near combustible materials.

     
     

4. Aesthetic Limitations

   • Repairs often leave visible patches, affecting curb appeal.

     
     

Types of Felt Roofing Systems

Type	Method	Best For	Lifespan
Torch-On	Layers fused with a blowtorch	Durable, long-term solutions	15–25 years
Self-Adhesive	Peel-and-stick application	DIY projects, small roofs	10–15 years
Cold Applied	Adhesive-based, no heat required	Repairs or budget installations	10–20 years.

Installation and Maintenance Tips

1. Professional Installation

   • Torch-on systems require certified roofers to ensure fire safety and proper sealing.

   • Ensure the roof deck is primed and debris-free before laying felt.

     
     

2. Routine Maintenance

   • Clear debris from gutters and drains to prevent pooling.

     
     

3. Repairs

   • Small splits can be sealed with bitumen tape or liquid adhesive.

   • For extensive damage, consider a full overlay or replacement.

     
     

Felt vs. Alternatives: Key Comparisons

Feature	Felt Roofing	EPDM/Single-Ply	Fibreglass
Cost	£30–£50/m²	£60–£100/m²	£70–£120/m²
Lifespan	10–25 years	30–50 years	25–30 years
Installation	Quick, DIY-friendly	Professional required	Professional required
Aesthetics	Limited colour options	Sleek, uniform finish	Smooth, customizable
Eco-Friendliness	Recyclable options	High recyclability	Long-lasting, low waste

When to Choose Felt Roofing

• Budget Constraints: Ideal for temporary structures or short-term solutions.

• Simple Repairs: Existing felt roofs can be cost-effectively patched.

• Non-Visible Areas: Garages or sheds where aesthetics are less critical.

Conclusion

Felt flat roofing offers a practical balance of affordability and functionality for UK homeowners. While its shorter lifespan and maintenance needs may deter long-term projects, it remains a go-to for budget-friendly, quick installations. For permanent structures, higher grade materials should be used but at a higher upfront cost. Regular upkeep and professional installation are key to maximizing felt’s performance, ensuring your roof stays watertight for years.