Felt Roofing — North London
Modern Felt Roofing
That Outlasts the Old
Pour-and-Roll by Decades
Today's torch-on felt systems are engineered for durability. We install three-layer modified bitumen systems that deliver reliable, leak-free protection at a price that works for every budget.
★ Three-layer systems · 15–20 year lifespan · Cost-effective alternative to EPDM
What Is Modern Felt Roofing?
Modern felt roofing bears little resemblance to the old-fashioned pour-and-roll method that gave felt a poor reputation. Today's systems use high-performance modified bitumen membranes reinforced with polyester or fibreglass, applied with a gas torch for a heat-welded bond that's far superior to the old adhesive methods.
Felt roofing is the most affordable flat roofing option, making it the right choice for garages, outbuildings, shed roofs, and situations where budget is a primary consideration. When installed correctly using a three-layer system, modern felt delivers 15–20 years of reliable, leak-free performance.
At AC Roofing & Carpentry Ltd, we only install multi-layer torch-on felt systems — never the single-layer self-adhesive products you find at DIY stores. Our three-layer approach includes a vapour barrier, a reinforcing base layer, and a mineral-finish cap sheet that provides UV resistance and durability.
We install felt roofs across North London on garages, extensions, porches, dormer cheeks, and small commercial buildings. For properties where a longer lifespan is needed, we also offer EPDM rubber and GRP fibreglass alternatives.
Why Old Felt Roofs Fail and What It Costs You
Old pour-and-roll felt roofs were constructed by mopping hot bitumen onto the deck and rolling out sheets of basic felt over it. This method relied on the bitumen maintaining its adhesion — which it rarely does beyond 10–12 years. As the bitumen dries and cracks, the felt separates from the deck, forms blisters, and water finds its way underneath.
Blistered felt is one of the most common sights on London garages and extensions. Homeowners often puncture the blisters, apply patch felt, and hope for the best. This approach is temporary at best and actively harmful at worst — each puncture and patch creates another potential failure point.
The real cost of a failing felt roof is the damage it causes to the structure beneath. Water pooling on a sagging, delaminated felt roof soaks through to the deck boards, rotting the timber and creating a spongy, unsafe surface. By the time the deck boards need replacing, the cost has increased significantly compared to a straightforward felt re-cover.
If your felt roof is blistered, cracked, or showing signs of separation at the edges, it's time to replace it — not patch it. A new torch-on system installed on a sound deck costs less than most people expect and eliminates the problem for 15–20 years.
How We Work
Our Felt Roof Installation Process
Inspection
We check the existing roof and assess the deck condition beneath.
Deck Preparation
Old felt is stripped and the deck is repaired or replaced where needed.
Three-Layer Application
Vapour barrier, base layer, and mineral cap sheet torch-applied in sequence.
Edge Details
Drip edges, upstands, and perimeter trims sealed for a watertight finish.
Completion
Final inspection, clean-up, and written guarantee issued.
Why It Matters
Why Choose Modern Felt Roofing
Most Affordable Option
Felt roofing costs less than EPDM or GRP while delivering solid performance.
Proven Technology
Modified bitumen has been used worldwide for decades with a strong track record.
Quick Installation
Most felt roofs are completed in a single day.
UV Resistant
Mineral cap sheets reflect UV and resist degradation from sunlight.
15–20 Year Lifespan
Three-layer systems outlast old pour-and-roll by a significant margin.
Suitable for Most Structures
Works on timber, concrete, and metal decks with proper preparation.
Felt Roofing: Technical Details and Specifications
Three-Layer System Explained
A professional felt roof system consists of three distinct layers, each serving a specific purpose. Layer one is a perforated vapour barrier that allows the deck to breathe while preventing moisture from below reaching the upper layers. Layer two is a reinforced base sheet — typically polyester-based — that provides the structural strength of the membrane. Layer three is the cap sheet, a mineral-surfaced membrane that provides UV protection, weather resistance, and a finished appearance. Each layer is torch-applied, creating a heat-welded bond between layers that far exceeds the durability of adhesive or cold-applied methods.
Modified Bitumen Types
Modified bitumen comes in two main types: SBS (Styrene Butadiene Styrene) and APP (Atactic Polypropylene). SBS membranes are more flexible and handle UK winters better — they remain pliable at temperatures well below freezing, reducing the risk of frost cracking. APP membranes are more UV resistant and better suited to hot climates. For London installations, we predominantly use SBS-modified systems for their superior cold-weather performance.
Deck Requirements
Felt roofing can be applied to several deck types. Plywood (18mm WBP marine ply) is the most common for residential applications. OSB3 (oriented strand board) is an acceptable alternative at a lower cost. Concrete decks are common on commercial buildings and older properties. The deck must be clean, dry, and structurally sound before any felt is applied — we always inspect and repair the deck as part of every installation.
When to Choose Felt Over EPDM or GRP
Felt is the right choice when budget is the primary concern and the roof doesn't need to withstand foot traffic. For garages, sheds, and outbuildings, modern felt offers excellent value for money. However, for extensions and habitable spaces where a longer guarantee is desired, EPDM or GRP may be worth the additional investment. We'll always recommend the system that best matches your needs and budget — never the one that earns us the most.
Common Questions
Frequently Asked Questions
Protect Your Property Today
Speak to our team for honest advice and a no-obligation estimate. Most quotes delivered within 24 hours.