Rotten eaves felt
What is eaves felt and why does it rot?
The short answer
Eaves felt is the strip of underlay, or a plastic eaves tray, that carries water from under the lowest tiles into the gutter. It rots because that edge stays wet longest: gutters overflow, tiles hold moisture, and sun and age break the felt down. Once it fails, water runs behind the fascia and into the rafter ends, so the damage is usually found as a rotten board first.
What the eaves felt does, why it is the first part of the underlay to fail, how to spot trouble early and what the repair involves.
What the felt at the eaves actually does
Under the tiles of a pitched roof lies a layer of underlay, and any rain that blows past a tile lands on it and runs downhill. At the bottom edge, the eaves, something has to guide that water over the fascia board and into the gutter. That something is the eaves felt, or on newer work a rigid plastic tray. The tiles at the edge, known as the eaves course, sit on top of it and overhang the gutter slightly.
When the job is done well, the felt droops gently into the gutter and the water never touches the timber. When it is short, torn or sagging, the water finds the gap between felt and fascia instead. It then runs onto the rafter feet, the cut ends of the sloping timbers that rest on the wall. Those are hidden behind the fascia, which is why this fault can go on for years without anyone looking at it.
Why this strip rots before the rest
Several things gang up on the eaves. It is the wettest point of the roof, because every slope drains across it. A gutter that overflows or sags tips water backwards, onto the felt and the board behind it. Leaves and moss collect along the edge and hold water against the underlay long after the rain has stopped. Where the felt is exposed to daylight, as it often is at the very edge, sun slowly breaks it down.
Age is the other cause. Older underlay is often a bitumen-based felt, and it goes brittle, splits along creases and loses its hold on the fixings. A tile that has slipped near the gutter lets rain straight in, and a bird or squirrel pushing at the gap makes it worse. Poor ventilation adds a further push, because condensation forms on a cold, still surface. Our answer on slipped roof tiles shows how one loose tile can start the whole chain.
Signs that show from the garden and the loft
Most of the clues show without a ladder. Look along the fascia for peeling paint, dark staining, a soft or spongy board, or a green line where water keeps running. Check the gutter for a dip or a leaking joint, and for a drip mark on the wall below. Upstairs, shine a torch along the loft edge where the rafters rest on the wall plate, the timber laid along the head of the wall. Dark, damp or crumbling timber there, or daylight at the eaves, points to a failed edge.
Please do not go onto the roof to look. Tiles at the edge are loose more often than they appear, and our answer on walking on roof tiles explains the risk. Binoculars and a few close photographs of the fascia tell a surveyor plenty before anyone goes up.
How the repair is done
The fix starts at the gutter, because replacing felt under a gutter that overflows only buys you a few seasons. We lift the lowest few courses of tiles, remove the old felt, check the fascia and the rafter feet, and cut out anything that is soft. Sound timber stays. Then we lay new felt or a tray so that it runs over the fascia into the gutter with a clean overlap, put the tiles back on a fresh batten line, and refit the gutter to a proper fall.
Ventilation matters here. For a cold roof under high-resistance underlay, Marley specifies a continuous opening at the eaves of 25mm where the pitch is 15 degrees or less, and 10mm where it is steeper. A repair that closes that gap with felt or insulation trades one problem for another. Where everything above is in good order, one stretch of eaves can be renewed on its own. Our guide to underlay and ventilation covers the detail.
How big the job gets, and what drives the price
Cost follows the length of eaves involved, the number of courses lifted, how much timber has to be replaced and how high the work is. A short run above a single-storey extension is a very different job from every elevation of a two-storey house. Scaffold is often the largest single item on a taller house. Checkatrade's roof replacement guide, updated in October 2026, puts typical UK scaffolding for a roof job at £700 to £1,300.
Once we have seen the fault and photographed it, the written quote reaches you as one total. Our pitched roofing page shows where eaves work sits among the other tiled roof repairs. Should the survey find the felt gone along one side only, we will say so and price that side alone, not push a full strip. Water that has already reached the wall plate or the ceiling below is a separate matter, and we point it out when we see it so it can be dealt with in the same visit.
Related questions
Eaves felt questions
Does a rotten fascia mean the eaves felt has failed?
Often, but not always. A leaking gutter or old paint can rot a fascia on its own. If the board is soft behind the gutter and the rafter feet show damp in the loft, the felt is the likely culprit. Photographs of both together let a surveyor tell which it is.
Can eaves felt be replaced without re-roofing?
Yes, where nothing else is wrong with the roof. The lowest courses of tiles are lifted, the felt or tray is renewed, and the same tiles go back. Broken ones are swapped for matching tiles. Whether it is practical depends on the age of the tiles and the state of the battens.