Sheds, workshops, summerhouses and log stores share a roofing problem: the structure is light, the roof is often close to the ground, and nobody budgets for it until the contents are getting wet. In the Stroud valleys many of these buildings stand under trees or tucked against a stone wall, which means leaves, shade and moisture are part of the job from the start.
This guide compares every sensible covering for a shed or outbuilding, so you can match the material to the building. If you only want a verdict on one option, our answer on felt shingles for a shed weighs those alone. Larger buildings, and the leaks that start the whole conversation, are covered in leaking garage roofs, and the wider work sits under garage roof replacement.
Start with the slope, the deck and the span
Three facts about the building decide which coverings are even on the table, and you can check all three in ten minutes with a tape and a spirit level.
The slope
A shed with a clear pitch, a ridge or a steep mono-pitch (a single slope) can take almost anything. A shed with a barely perceptible fall is effectively a flat roof, and needs a continuous waterproof membrane, not overlapping pieces. Many garden sheds sit in the grey area between the two. If water pools anywhere on the surface after rain, treat the roof as flat.
The deck
Most sheds have a deck of boards or sheet timber under the covering. The deck must be sound and dry. Soft, spongy or black patches mean the leak has been running a while, and the board is replaced before anything new goes over it. Putting a new covering onto a wet deck traps the damp.
The span and the frame
A thin shed frame cannot carry a heavy covering. Felt and EPDM weigh little; tiles and slate do not belong on a shed. If you plan to stand on the roof to work, the deck and the joists need to be strong enough to take it, and the sensible answer is to avoid it altogether and work from a ladder with a board.
Outbuildings that are old
A stone outbuilding or a barn conversion is a different animal. Roofs on such buildings may carry stone slates or clay tiles, and they may be listed. Our guide to garage conversion roofs deals with the insulation and Building Regulations questions that apply once a building is lived in or used as a room.
Bitumen felt: the traditional shed covering
Felt is what most sheds start with. A roll of bitumen-impregnated fabric is nailed or stuck down in overlapping strips, working from the eaves up, with the upper strip overlapping the lower so water runs over the joints, not into them. It is cheap, quick and, for a plain shed, perfectly adequate.
Grades of felt
Cheap shed felt is thin and short-lived. Heavier roofing felt in a reinforced grade is a better covering, and built-up felt of two or three layers, as used on garage flat roofs, is better again. Tearing, blistering and splitting at the folds are the usual failures. Sunlight dries bitumen out, so the south slope tends to go first.
Life and cost
The Less cost guide, updated March 2026, reckons a good felt job can reach 20 years while a poor one may fail inside 10. Other sources, such as the CORC guide, give longer figures for well-maintained felt, so the range is wide and workmanship drives it. On cost, For a flat roof, MyBuilder's 2026 figure for bitumen felt is £70 to £100 per m²; that is a garage-scale price and a small shed needs less preparation. A shed of a few square metres is a small job, and the quote reflects that.
Fixing details
The felt turns up at the edges and is fixed under a drip batten, or over a drip edge, so that water drops clear of the wall. Nails go at the laps, with clout nails driven flat but never through the face of the sheet where water runs. Where the felt meets a house or garden wall, a flashing or a sealed upstand is what keeps rain out. If the old roof was repaired as a patchwork, a clean strip is usually better than another patch; our guide on leaking garage roofs covers when to repair.
Felt shingles: a pitched-roof option
In British usage, a shingle on a shed means a felt shingle: a small, flat piece of bitumen-coated mat with a granule surface, sold as individual tabs or in strips and laid in overlapping courses on a boarded roof. They are the look of a tile roof at the cost of a felt one, and many people choose them for summerhouses and garden buildings for that reason.
What they need
Shingles shed water by overlap, the way tiles do, so they need a pitch. A very shallow slope lets wind-driven rain lift the tabs and pass underneath. The maker's literature sets the minimum pitch for each product, and a mono-pitch shed with a gentle slope is often below it. A solid deck is essential, and they are nailed in a set pattern, with the nail heads covered by the course above.
Where they work and where they do not
On a steep, simple roof with no valleys or chimneys they are an easy cover to lay, and a patch is straightforward. In a gale they can lift, and on a flat or near-flat roof they are the wrong tool. We have set out the full case for and against in the sibling answer on felt shingles for sheds, so this guide does not repeat it.
Checking the deck first
Because shingles are nailed through the deck, a sound surface matters. Boards that are warped, split or lifting will show through the shingles within a year or two. We check the deck as the old covering comes off, and replace any board that fails the test.
EPDM rubber for sheds and low roofs
EPDM is a synthetic rubber membrane sold in large sheets, often a single piece cut to fit the whole roof. Adhesive holds it to the deck, the edges turn up the walls, and ready-made pieces finish the corners. There is no seam across the middle of the roof to fail, which is why it suits flat and shallow-pitch sheds and outbuildings so well.
Life and cost
Sources vary a good deal. GreenSpec quotes 20 to 30 years, the Building Centre says more than 25 years, and Less quotes 30 to 50. The safe wording is 20 to 30 years or more, and the figure depends on workmanship and the roof's exposure. For a flat roof, MyBuilder's 2026 guide puts EPDM at £90 to £130 per m², and a small shed will sit at the low end of the total, though small jobs seldom cost less per metre because the set-up time is the same.
What it asks of the deck
The deck needs to be clean, dry, smooth and free of nail heads, because the rubber is thin and will show every lump. A fall is built in so that water leaves the roof: BS 6229 calls for a design fall of 1:40, with 1:80 as the finished minimum, and a shed deck that is dead level is corrected with firring strips before the membrane goes down.
Edges and outlets
On a lean-to shed, water runs to one edge and into a gutter or over a drip trim. We set the trim so the water clears the wall, and check the gutter runs gently towards its outlet. Makers' guidance spans roughly 1:600 to 1:350, depending on the system. Neglected, the gutter becomes the reason for the next leak.
Trees and leaves
EPDM tolerates leaf litter better than felt, but a deep bed of wet leaves still holds moisture against the edge detail. A sweep every autumn is all it needs.
Sheet coverings and GRP
Where the shed is basic and the owner wants a quick fix, profiled sheet is an option. Metal and bitumen-based sheets are fixed to timber purlins and shed rain quickly. For garages, this material gets its own treatment in our guide to box-profile roofs; on a shed the same principles apply at a smaller scale. A sheet roof is loud in the rain, which matters for a workshop or a studio, and it needs ventilation under it if the building holds anything damp.
GRP
GRP (glass-reinforced plastic) is fibreglass laid in resin over a deck, forming a joint-free, rigid skin. Less puts its life at 25 to 40 years, and CORC gives 25 or more if well maintained. MyBuilder's 2026 flat roof figures put GRP at £95 to £150 per m². It suits workshops and larger outbuildings where a hard-wearing flat roof is wanted. It is less forgiving of a flexing deck: if the shed frame moves, the skin can crack, so a rigid, well-fixed deck matters.
Comparing the options
| Covering | Suits | Typical life (sourced) | Weak point |
|---|---|---|---|
| Bitumen felt | Small, plain sheds | 10 to 20 years (Less) | Splits at folds and laps |
| Felt shingles | Pitched summerhouses | Not quoted here | Lift in wind, need pitch |
| EPDM | Flat and shallow roofs | 20 to 30 years or more | Edge detail, deck finish |
| GRP | Workshops, larger roofs | 25 to 40 years (Less) | Cracks if the deck moves |
| Profiled sheet | Basic stores | Not quoted here | Fixings, laps, noise |
Choosing, and what the job involves
Choose by slope first, because the slope rules some coverings out. Then weigh how long you want it to last, how much work you want to do, and what the building is for. A cheap felt roof on a shed that holds a lawnmower is rational. The same roof on a studio with electrics is not.
Doing it yourself, or not
A competent person can felt a small shed. EPDM, GRP and anything with edge trims or roof-to-wall flashings reward experience. We would not suggest climbing onto a shed roof, particularly a brittle one, without a plan for spreading your weight.
Old and listed outbuildings
If a stone outbuilding stands in the curtilage of a listed house, ask the council early. Stroud District Council advises checking the status of curtilage structures with its conservation department, and a re-roof in a different material can change the character of the building.
Planning and rules
Like-for-like re-roofing of an outbuilding does not normally need planning permission. Changing the covering to something noticeably different, on a building in a conservation area or the Cotswolds National Landscape, is worth a call to the planning team first. A small shed that is not being lived in does not raise the insulation and Building Regulations questions that a conversion does.
What our survey looks at
The survey covers the slope (with a level), the deck (pressed and probed), any rot at the foot of the posts, and the edge details. Your written quote follows, covering materials, labour and waste, and the work is guaranteed for 10 years in writing. Send photographs through the form or WhatsApp, or call 01453 933613.