In short
Look in the loft. Felt that has failed is torn, brittle or sagging between the rafters, often worst at the bottom of the roof where it dips behind the gutter, and you may see daylight or water marks on the timbers. Inside the house, brown stains or peeling paint that appear after rain are a common sign. If the damage is in one area, a local repair is often all it needs.
This is a job for our Roof Repairs service.
What the felt does
The tiles or slates shed most of the rain, but not all of it. Underneath sits a layer of felt or membrane that catches whatever is driven past them. The Federation of Master Builders describes a breathable underlay as one that "protects against wind-driven rain while allowing moisture vapour to escape". When that layer fails, the roof can look perfect from the street while water gets in.
Signs to look for in the loft
- Torn or shredded felt, especially between the rafters.
- Felt that crumbles when touched. Old bitumen felt goes brittle with age.
- Sagging at the eaves. The bottom metre of felt dips behind the fascia, holds water and rots.
- Daylight through the roof. Which? says that if you can see daylight, call a professional promptly.
- Dark marks or wet patches on rafters and battens.
Signs inside the house
The FMB lists "brown ceiling marks, peeling paint or drips that appear after rain" as early warnings. A damp patch at the top of an outside wall, or along the ceiling near the eaves, often points to felt failing at the bottom of the roof.
Repair or re-roof?
This is the question that matters, and the honest answer depends on how much of the felt has gone.
| What we find | What it usually needs |
|---|---|
| Felt rotted along the bottom of the roof only | Open up the bottom metre, new felt lapped into the old, eaves support tray fitted |
| A leak by a chimney or wall | New lead and a short length of new felt around it |
| Felt torn or brittle across the whole roof | Strip and re-roof with a new breathable membrane and treated battens |
The FMB says repair may suit when damage is confined to a small area, and replacement may be needed when leaks keep returning despite competent repairs. On one Bedford house we cured a chimney leak with new lead and about a metre of felt. On other roofs the felt has failed from top to bottom, and a re-roof is the honest answer. Each was the right call for that roof.
What we do
- Check from the loft and the roof, and photograph the felt.
- Show you the photos and explain what has failed and where.
- Quote in writing for the repair that fits, not the biggest one.