Torch-On Felt
(0 Products)Torch-on felt is a type of roofing material primarily used for waterproofing flat roofs. The process of applying torch-on felt involves heating the bitumen backing of the material with a propane torch. This melting of the bitumen allows it to bond seamlessly with the surface below, forming a secure and continuous layer that acts as a barrier against water infiltration.
What Is Torch-On Felt?
Torch-on felt is a type of modified bitumen roofing membrane applied using a propane gas torch. The felt is rolled out across the roof deck and bonded as it’s heated, creating a fully-adhered, seamless, and watertight barrier.
The membrane is typically reinforced with polyester or fibreglass to provide dimensional stability, crack resistance, and strength. The surface of the top layer is often finished with mineral granules to offer UV protection and reduce surface degradation.
Key Composition
- Modified Bitumen: Styrene-Butadiene-Styrene (SBS) is often used to enhance the material’s elasticity, enabling it to expand and contract with temperature fluctuations. Without this modification, bitumen would remain rigid, leading to cracks and potential leakages over time.
- Carrier Material: Reinforced with polyester, glass fibre, or a composite for added durability.
- Surface Finish: Mineral, sanded, or foil-faced depending on layer type and usage.
Applications
- Flat & Low-Slope Roofs (Commercial & Domestic)
- Garages, Extensions & Porches
- Garden Rooms & Outbuildings
- Balconies (with suitable overlay)
- Refurbishments & Overlays on Existing Systems
Benefits
- Waterproofing: Torch-applied bonding creates a fully sealed surface with no mechanical fixings or overlaps vulnerable to water ingress.
- Long Lifespan: Well-installed systems can offer service lives exceeding 20 years with routine maintenance.
- UV & Weather Resistant: Cap sheets are mineral-coated to resist harmful UV rays, wind uplift, and temperature extremes.
- Resistant to Ponding Water: Unlike some single-ply or painted-on systems, torch-on felt can tolerate standing water when applied with correct falls and outlets.
- Low Maintenance: Requires minimal upkeep compared to liquid-applied systems or felt tacked with nails.
Torch-On Felt vs. Other Roofing Materials: A Comparison
When considering roofing materials, it's important to compare the benefits and limitations of torch-on felt with alternatives like EPDM, PVC, and traditional felt systems.
- Durability: Torch-on felt typically outperforms traditional felt due to its enhanced waterproofing and flexibility, offering superior protection against the elements.
- Ease of Installation: Unlike other roofing membranes that may require adhesives or mechanical fixings, torch-on felt bonds securely with the heat of a propane torch, creating a seamless, hassle-free application process.
- Cost-Effectiveness: Although installation may require specialised equipment (propane torch), the longevity and minimal maintenance requirements of torch-on felt often make it a more cost-effective option in the long run.
Frequently Asked Torch-On Felt Questions
What Is The Difference Between SBS And APP Torch-On Felt?
- SBS (Styrene Butadiene Styrene) felt is more flexible and better suited to colder climates, making it ideal for UK roofing. It offers excellent elasticity, allowing it to accommodate roof movement.
- APP (Atactic Polypropylene) felt is more UV-resistant and often used in hotter climates. It becomes pliable at higher temperatures and is less commonly used in UK installations.
Can I Install Torch-On Felt Myself?
While it’s technically possible, torch-on felt installation involves the use of open flame (a gas torch), which poses a fire and safety risk. For this reason, it’s strongly recommended that torch-on felt is applied by a trained roofing professional. If you're looking for a DIY option, consider self-adhesive roofing felt instead.
How Long Does Torch-On Felt Roofing Last?
When correctly installed, torch-on felt can last between 15 to 25 years, depending on the product quality, installation method, and maintenance. Regular inspections and minor repairs can extend its service life.
Is Torch-On Felt Waterproof?
Yes. Torch-on felt is designed to be 100% waterproof when applied correctly. The heat bonding process ensures a seamless finish with no gaps or overlaps that could let in moisture. It’s particularly effective at dealing with standing water, making it ideal for flat roofs.
What's The Difference Between Cap Sheet And Underlay?
- Underlay is the intermediate layer that adds strength and flexibility. It’s usually sanded or plain-surfaced and goes beneath the cap sheet.
- Cap sheet is the top, weatherproofing layer, often finished in coloured mineral granules to protect against UV and wear. It’s the visible final layer of the roof.
Can Torch-On Felt Be Used On Pitched Roofs?
Torch-on felt is designed for flat or low-pitched roofs (usually up to 10°). It’s not suitable for steeply pitched roofs as gravity can cause the felt to lose its adhesion over time and the membrane may not remain properly bonded to the surface.
What Tools Do I Need To Install Torch-On Felt?
Professional installers typically use:
- Propane gas torch with regulator and hose
- Roofing knife or scissors
- Roller or weighted bar for smoothing
- Fire extinguisher (mandatory on site)
- PPE: gloves, goggles, fire-resistant clothing
