Old felt versus modern felt
The felt on many 1960s to 1990s garages and extensions was a basic sheet, often laid in hot bitumen and finished with stone chippings. Over the years sunlight dries it out, the chippings wash into the gutter, and the surface starts to crack like dried mud. That's the felt people think of when they say felt doesn't last.
Today's torch-on felt is a different product: reinforced, polymer-modified layers fused to each other with a gas torch to form a thick, bonded build-up. A typical system has an underlayer and a mineral-surfaced cap sheet that resists sunlight. Laid well, it is a solid, cost-conscious option.
When felt is the right choice
- When neighbouring roofs or adjoining sections are felt and the details need to match.
- On larger plain roofs where the budget matters most.
- Where a built-up system is preferred over a single sheet.
On small fiddly roofs or ones near timber cladding we may suggest a cold-applied system instead. Rubber is compared on our EPDM rubber roofs page.
Signs your felt has had its day
- Crazing or cracks across most of the surface, not just one area.
- Bubbles that squelch when pressed, meaning water is trapped under the layers.
- Felt that has pulled away from the edge trim or slumped at the upstand.
- Bare patches where the mineral finish has worn off.
- A deck that dips or flexes underfoot.
One or two of these in a single area usually means a repair. Several together across the roof point to replacement. Our flat roof repair page explains what a felt patch involves.
Replacing a felt roof
A replacement means stripping all old layers, checking and renewing boards where needed, and building up the new felt from the deck, with upstands taken up the wall and lapped under flashing. New trims and outlets complete it. On a garage, this is often combined with other improvements, which we cover on our garage roof replacement page.
Specify the layers, not just a new top surface
A felt roof proposal should make clear whether the work is a local patch, an overlay or a full strip and replacement. Those are not interchangeable. An overlay retains layers below, so their adhesion and moisture condition matter; stripping allows the deck to be examined directly. Ask how the decision is reached and which edges, outlets and upstands are included. The cap sheet is visible, but the supporting build-up is just as important to the finished roof.
At a wall, the layers need a properly formed termination rather than a coating brushed against brickwork. At a drip edge, the finish should discharge into the rainwater system instead of behind it. These details help explain why two felt roofing quotes for the same footprint can cover different amounts of work. Tell the roofer about adjoining coverings and any rooflight so their connections can be specified before materials are chosen, particularly where the new felt meets a part that is being retained.
Keep checks observational: a window photograph can show surface changes without testing blisters or walking across uncertain boards. Mention how long the mark indoors has been present and whether earlier patches were made at that spot.
Finding local felt roofers
Whoever you choose, ask how they'll treat the edges and wall junction, whether they'll lift the old felt or cover it, and how they'll protect nearby timber from the torch. For the things that move the price, read our flat roof cost guide.
We lay and repair felt roofs across Somerset and Devon within about 50 miles of Taunton. Call 07399 680142 or get in touch for a free written quote, or see every option on our flat roofs page.