A shed felt roof lasts when the deck is flat, edges are capped, and every lap is sealed so water can’t creep underneath.
A felted shed roof looks simple from the ground. Up close, it’s a chain of small choices: where you start the first strip, how straight the drip line sits, how tight the laps land, and whether the corners are folded so rain has no path in. Get those bits right and a budget roll of felt can hold up for years. Rush them and you’ll be chasing drips after the first hard spell of rain.
This walkthrough is built for the most common garden shed roof styles: apex (two slopes) and pent (one slope). It sticks to practical steps you can do with basic tools, plus a few habits that save headaches later.
Before You Start, Check The Roof Pitch And Water Run
Felt likes a roof that sheds water, not one that holds it. Stand back and look at the slope. On a pent shed, water should run to the low edge with no sagging between rafters. On an apex shed, both sides should fall away from the ridge.
If the deck bows, water pools. Pools shorten felt life and can work into laps. Fix the deck now, not after the felt is down. Add noggins, swap a warped board, or re-screw loose panels so the surface turns flat again.
Check overhangs too. A small overhang helps water drip clear of the wall. If the roof ends flush with the wall, add a drip edge or a timber fillet so water doesn’t track back under the edge line.
Choose The Right Felt And Fixings For A Shed Roof
There are three common options for shed felting: plain bitumen felt, mineral-surfaced felt, and heavier reinforced systems sold as “shed felt” rolls. For most garden sheds, a mineral-surfaced top layer is the sweet spot: it shrugs off sunlight better than bare felt and takes scuffs a bit better.
If you’re comparing rolls, read the product sheet. It usually spells out lap sizes, edge overhang, and nail spacing. IKO’s shed felt data sheet is a solid reference point for typical overlaps and fixing patterns. IKO shed felt technical data sheet lays out practical fitting notes like edge overhangs and nail spacing.
Pick nails made for the job: galvanised clout nails with large heads. Small-head nails cut into felt. Rust-prone nails stain the mineral surface, then loosen.
Adhesive can be handy for laps and details. If you use a solvent-based felt adhesive, treat it like a flammable liquid and read the safety sheet for ventilation and ignition warnings. Bostik FelFix bituminous felt adhesive safety data sheet lists hazard statements and handling notes.
Set Up Safe Access Before You Lift A Roll
Even a small shed roof can bite. Felt rolls are awkward, and stepping backwards while lining a lap is when people slip. Use a stable ladder, set it on firm ground, and avoid stretching sideways. If you can, work from a platform tower or a sturdy workbench beside the shed so you’re not perched on the top rungs.
For ladder basics and setup angles, the Health and Safety Executive spells out sensible ladder use and checks. HSE ladder safety guidance is written for work sites, yet the habits carry straight over to home jobs.
If your shed roof sits high or the ground slopes away, use fall protection gear or get help. OSHA’s fall protection notes for construction cover restraint and edge risks in plain language. OSHA fall protection fact sheet explains system basics and why edges are the danger zone.
Prep The Roof Deck So Felt Sits Flat And Stays Put
Felt only performs as well as the surface under it. Start by stripping old felt, old tacks, and any brittle adhesive ridges. Scrape down high spots. Pull proud nails. Fix any soft patches by replacing the board or panel section.
Then tighten the deck. Run screws into any board that lifts, and add fixings along panel edges where you see movement. If the shed uses OSB or plywood sheets, check the joins. A ridge at a join will telegraph through the felt and can chafe it over time.
Finish with a quick sweep and a wipe. Grit under felt acts like sandpaper when the roof expands and contracts. Aim for a clean, dry surface. If the deck is damp, wait. Adhesive won’t grab well on wet timber, and moisture trapped under felt can bubble when the sun hits.
Measure And Cut Felt Strips Without Guesswork
Measure the roof width and length, then add your edge overhang. A common target is around 50 mm over the eaves and gable edges, yet follow the roll’s sheet if it states a different figure.
Plan your strip layout so laps shed water. That means lower strips go on first, then upper strips overlap them so water runs over the lap, not into it. On an apex roof, start at the eaves on one side, work up to the ridge, then repeat on the other side, finishing with a ridge cap strip.
Cut strips on a flat surface with a sharp knife and a straightedge. Let the felt relax before fitting. A roll stored tight can curl hard. Unroll it and leave it flat for a short while so it behaves on the roof.
Felt Roofing A Garden Shed Roof With Clean Lines
This is the core sequence that keeps water out and edges tidy. Read through once, then start. The steps are written so you can pause between them without losing the plot.
Step 1: Fit The First Eaves Strip Dead Straight
Start at the lowest edge where water leaves the roof. Lay your first strip so it overhangs the eaves by your chosen amount. Check it is square to the roof edges. If the first strip wanders, every strip after it will look crooked.
Tack the top edge first with large-head galvanised nails. Keep nails high enough that the next strip will cover them. Space nails evenly. If your felt sheet recommends a spacing pattern, follow it.
Step 2: Fix The Side Edges And Corners So Wind Can’t Lift Them
Fold the overhang down over the fascia or edge board. On gable edges, make neat corner folds rather than bunching. Use small relief cuts where needed so the felt lies flat with no wrinkles.
Nail the edge line at close intervals so wind can’t get a bite under it. Keep nails on the vertical face where possible, not on the flat roof surface near the edge where water runs.
Step 3: Add The Next Strip With A Clean Lap
Lay the next strip above the first. Set your lap width, then snap a chalk line or mark a few points so the overlap stays even from one end to the other. Uneven laps are where drips start.
Lift the lap edge, spread felt adhesive in a thin, even band, then press it down firmly. Work from one end to the other to push out trapped air. Once the lap is seated, nail the top edge of the upper strip, again keeping nails where the next strip will cover them.
Step 4: Work Up The Slope And Keep Water Running Over Laps
Repeat strip by strip up the roof. Keep checking alignment at the edges. Small corrections early save ugly trimming later.
On a pent roof, the final strip lands at the high edge. Wrap that strip over the top edge and down the back face so wind-driven rain can’t sneak in at the top.
Step 5: Cap The Ridge On An Apex Roof
Once both sides are felted up to the ridge, add a ridge cap strip. Center it along the ridge so it covers both top edges with equal overlap.
Bond the underside edges with adhesive, then nail down the outer edges where they meet the top surface of each slope, keeping nails away from the ridge line. Press it down tight so there’s no hollow that can flap.
Step 6: Finish Edges Neatly And Seal Any Awkward Details
Trim excess felt with a sharp blade and straightedge. If you have a barge board, fold felt over it for a tidy edge line. If you have exposed timber edges, add a drip edge strip or a metal trim to direct water away.
For sheds with vents, skylights, or flue pipes, treat the detail like a mini roof. Cut a snug hole, then add a patch piece above the penetration so laps still shed water. Seal the top edge of the patch with adhesive and press it hard.
Materials And Decisions That Make Or Break A Shed Felt Roof
Once you’ve laid a few strips, you start to see what matters: a flat deck, steady laps, and edge fixing that resists wind. This table pulls those choices into one place so you can check your setup before you commit to the full roof.
| Item Or Choice | What It Does On The Roof | Practical Tip |
|---|---|---|
| Mineral-surfaced top felt | Handles sun and scuffs better than bare felt | Cut with a fresh blade to avoid tearing the mineral face |
| Galvanised clout nails | Holds felt without rusting through | Use large heads so the felt can’t pull over the nail |
| Flat, tight roof deck | Stops puddles and chafing | Re-screw loose panels and replace soft boards before felting |
| Consistent lap width | Keeps water running over joins | Mark a line or points so the overlap stays even end-to-end |
| Adhesive on laps and details | Seals edges and blocks capillary creep | Use thin, even spread; press down from one side to the other |
| Edge folds and corner relief cuts | Prevents wrinkles that trap water | Make small relief cuts so felt lies flat on the fascia |
| Ridge cap strip (apex roofs) | Covers the top seam where wind-driven rain hits | Center it carefully, bond the edges, then nail away from the ridge |
| Dry-weather install window | Helps adhesive bond and avoids trapped moisture | Pick a calm, dry day so strips don’t flap while you align them |
How To Keep Laps Sealed In Cold Or Windy Weather
Cold felt is stiff. Wind turns it into a sail. You can still get a clean finish, yet you need a bit more patience.
Warm the felt roll in a shed or garage so it unrolls without fighting you. Carry strips up one at a time, not the full roll, so you’re not wrestling weight on a ladder.
For adhesive, read the product notes and allow time for it to grab. Some adhesives stay tacky longer in low temperatures. Keep lids closed between uses so the solvent doesn’t flash off in the tin.
If gusts pick up, stop and tack the strip lightly in place, then come back to the lap bonding once the strip is under control. Trying to spread adhesive on a flapping lap is messy and wasteful.
Neat Edge Trims And Drip Control Without Fancy Parts
A shed roof fails at edges more often than in the middle. Water clings to surfaces, then tracks back under a lip. The fix is simple: a sharp drip line and a clear path away from timber.
If your shed has no fascia board, you can still fold felt down over the edge and nail it to the face board. Keep the bottom edge straight so water drops cleanly. If you want a sharper finish, add a basic metal drip trim before felting, then run the felt over it and nail where the trim allows.
At gable edges, keep the felt tight and smooth. Wrinkles near the edge catch water and invite wind lift. A few small relief cuts can turn a messy corner into a flat, crisp fold.
Common Shed Roof Felt Problems And Quick Fixes
Most issues show up in the first season: a lifted edge, a lap that weeps, a bubble that grows on hot days. Fixing early stops water getting into the deck.
| Problem You See | Likely Cause | Fix That Works |
|---|---|---|
| Edge flapping in wind | Nails too far apart on the vertical edge | Re-nail the edge line with closer spacing; add a thin bead of adhesive under the lift |
| Drip line runs back onto the wall | Overhang too short or edge not folded clean | Add a drip trim or extend the felt with a bonded edge strip |
| Lap weeps after rain | Lap bonded onto dust or damp timber | Lift the lap, clean and dry it, then re-bond with fresh adhesive and firm pressure |
| Bubbles on sunny days | Moisture trapped under felt or adhesive skinned too soon | Slice the bubble, let it dry, then patch with a felt piece that overlaps all sides |
| Small splits near nail heads | Head too small or felt pulled tight across a ridge | Patch over the split; on the next roof, use large-head nails and flatten deck joins |
| Ridge cap edges lifting | Cap not bonded or pressed down evenly | Lift, apply adhesive, press tight end-to-end, then re-nail the outer edges |
| Water pooling mid-roof | Deck sag between supports | Add support under the deck; patching felt alone won’t stop a sag from returning |
Maintenance Checks That Extend Felt Life
A felt roof doesn’t ask for much, yet a quick check now and then can stop a small flaw turning into a rotten deck.
After a heavy storm, scan the edges and ridge line. Look for lifted corners and any place where the mineral surface has worn through. Clear leaves and moss so water can flow off the roof without damming at the edges.
If you store ladders, bikes, or timber beside the shed, keep them from rubbing the roof edge. Repeated bumps at the same spot can loosen nails over time.
When you spot a scuff or a small tear, patch it. Cut a patch piece with rounded corners, bond it down with adhesive, then press hard from the center out so no air stays trapped.
When To Re-Felt Instead Of Patch
Patches work well for isolated damage. Re-felting makes more sense when the felt is brittle across wide areas, when multiple laps have started to lift, or when you see repeated bubbling across the roof surface.
If the deck under the felt is soft, treat that as the real issue. Replace the deck section, then re-felt. Laying fresh felt on weak timber only hides the problem until the next rainy stretch.
If you want a spec reference for reinforced bitumen sheets used in roofing work, BS EN 13707 sets definitions and characteristics for reinforced bitumen sheets. BS EN 13707 standard overview explains the scope and product category for roofing sheets.
References & Sources
- IKO.“Technical Data Sheet (TDS) IKO Shed Felt.”Provides typical shed felt fitting notes such as overhangs, laps, and fixing patterns.
- Health and Safety Executive (HSE).“Safe Use Of Ladders And Stepladders.”Outlines safe ladder selection, setup, and use habits that reduce fall risk during roof work.
- Occupational Safety and Health Administration (OSHA).“Fall Protection In Construction (Fact Sheet).”Explains fall protection basics and why roof edges and openings are high-risk zones.
- Bostik.“Safety Data Sheet: Bostik FeltFix Bituminous Felt Adhesive.”Lists hazard statements and handling precautions for a solvent-based bitumen felt adhesive.
- British Standards Institution (BSI).“BS EN 13707:2013 Standard Overview.”Summarizes the scope and characteristics for reinforced bitumen sheets used for roof waterproofing.