How to felt a shed roof

Inspired by the official Wickes how-to guide. This walk-through is based on the Wickes tutorial "How to Felt a Shed Roof | Wickes", which covers the full process from stripping back to finishing, including the overlapping technique that stops water tracking under the felt. A solid watch before you climb the ladder.

1. Check the roof boards and rafters first

Before you spend any money on felt, get up and have a proper look at the underlying structure. Press down on the boards across the roof. Any that feel soft, spongy or that give under pressure are rotten and need replacing before you do anything else.

Check the rafters too. A single rotten batten can be replaced in an afternoon. Carry on regardless and the new felt will just leak through the same rotten wood inside a season.

2. Remove all the old felt

Pull back the old felt carefully, starting at the ridge. Most shed felt is held down with galvanised clout nails — you'll need a claw hammer or pry bar to lift them. Take out every nail you find; leaving old nails in the boards creates bumps that will tear the new felt over time.

Clear away the old material and give the roof boards a brush down. Check for any protruding screws or sharp edges and deal with them before laying anything new.

3. Cut and lay the first felt strip at the eaves

Start at the bottom of the roof, not the top. Roll out the felt along the eaves edge, leaving a 50 mm overhang beyond the fascia board so rainwater drips clear of the timber frame.

Nail along the top edge of the strip using galvanised clout nails, spacing them about 100 to 150 mm apart. Keep the felt taut as you go — but don't pull it so tight it splits at the corners.

4. Work up the roof, overlapping each strip

Each new strip of felt should overlap the one below it by at least 75 mm — 100 mm is better for a particularly exposed roof. This overlap is what stops wind-driven rain from tracking backward under the felt.

Nail along the top edge of each strip. You don't need to nail through both layers where they overlap; just nail the top edge of the upper strip, which holds both in place.

5. Fold and secure the side edges neatly

At the gable ends, fold the felt down over the barge boards and nail or staple it in place. Trim any excess so it sits flat. A neat fold keeps water away from the end grain of the boards below.

To be fair, this is the fiddly part. Take your time at the corners — a tidy mitred fold looks far better than a lumpy scrunch of material, and it seals better too.

6. Fit the ridge cap

Cut a strip of felt wide enough to fold over both sides of the ridge by at least 150 mm on each side. Lay it centrally along the apex of the roof and nail down both edges, working from one end to the other.

The ridge cap is the most exposed part of a shed roof, so use plenty of nails along both edges — about 100 mm spacing. This is where a lot of shed roofs fail first when the cap lifts in high winds.

7. Check all edges and press down any loose spots

Walk the perimeter of the roof and run your hand along all the edges. Any loose or lifted sections need a nail or two to pin them down now, before the first wet weather finds them.

Give the fascia and barge boards a coat of wood preservative while you have the ladder out. It won't take long and it adds years to the lifespan of the whole structure.

When to call a handyman

Call Richard if the roof boards or rafters are significantly rotten, the shed is large enough that working at height becomes awkward, or you'd simply rather not spend a Saturday on a ladder in the wind. A re-felt typically takes a few hours and leaves you with ten years of peace of mind.