Plenty of garages in the Stroud valleys have a ridge and two slopes rather than a flat deck. Some were built with the house and carry the same tiles. Others, usually the detached and the later ones, wear corrugated sheet on a lightweight timber frame. A pitched garage roof sheds water by gravity, so it is forgiving in a way that a flat roof is not. A slipped tile or a failed ridge can sit unnoticed for years, because the garage is rarely heated and nobody looks up.
This guide covers the pitched garage as it already exists: the coverings, the timber underneath, the faults we look for on a survey and the point where replacement beats repair. A flat garage that someone wants to turn pitched is a different job, set out in our answer on converting a flat garage roof to pitched. For the full range of garage work, from felt to asbestos cement, start at garage roof replacement.
What a pitched garage roof is made of
Strip away the covering and nearly every pitched garage roof has the same bones. Rafters run from the ridge down to a wall plate on top of the side walls. Across the rafters sit battens, the thin timber strips that tiles hang from, or purlins (heavier horizontal timbers) where sheet is used. Between covering and rafters there may be an underlay, a sheet laid under the tiles to catch rain driven past the laps. Many older garages have no underlay at all, which is one reason their undersides look stained.
The covering on top falls into a few families:
- Concrete interlocking tiles. Heavy, common on garages built with a house, and long-lived.
- Clay plain tiles or pantiles. Seen on older and more traditional outbuildings.
- Natural slate. Less common on garages, usually where the main house is slate.
- Corrugated cement sheet. Very common on mid-century garages, and sometimes asbestos cement (see below).
- Profiled metal sheet. Light steel panels, covered in our guide to box-profile roofs.
Gables and verges
A verge is the sloped edge of a roof where it ends at a gable. A tiled verge is normally finished with mortar or a dry-fix trim, and it takes more weather than any other detail on the roof, because wind gets under it. Sheet roofs finish with a bargeboard or a metal trim.
Why the structure matters for the covering
Concrete tiles are far heavier than sheet. A garage frame designed for sheet usually cannot take tiles without strengthening, a point we return to under replacement. The reverse also holds: a tile roof swapped for light sheet may lose the weight that held the rafters down in a gale, so the fixings back to the wall plate become the thing to check.
Tiled pitched garage roofs: pitch, life and fixings
A tile only works above a certain slope. Marley's published data gives the minimum pitch for each of its tiles, and it varies a lot: 15° for its Mendip and Wessex concrete tiles, 17.5° for Edgemere, 22.5° for Double Roman, and 35° for its concrete plain tile. The manufacturer's own sheet for your exact tile is the only safe reference, because a tile laid below its minimum pitch can let rain blow up under the laps. Garage roofs are often built at a shallow angle to save height, which is why pitch is the first number we measure when a customer asks for a different tile.
How long tiles last
Lifespan ranges are wide and the sources disagree. MyBuilder puts concrete tiles at 30 to 50 years, and Marley refers to around 60 years while stating that this is not a guarantee. Clay is quoted at 40 to 60 years by MyBuilder. Treat these as typical ranges that rest on exposure, workmanship and maintenance. On a garage, the tiles often outlast the things holding them: the battens, the mortar at the ridge and the nails.
Ridge and hip fixings
Under BS 5534:2014, ridge and hip tiles are held by mechanical fixings as well as mortar, since a bed of mortar was judged too weak to hold them alone. Plenty of older garages were bedded in mortar only. When that mortar cracks, the ridge tiles loosen and can slide. MyBuilder's 2026 figures give £300 to £600 for re-bedding or replacing the ridge tiles, and the same site prices a dry ridge system at £40 to £60 per metre.
Underlay and ventilation
If the garage is ever lined or converted, ventilation becomes a design question rather than an afterthought. Marley, citing BS 5250, sets out a continuous 5 mm gap at high level for a lean-to or mono-pitch, and wider eaves gaps for shallow roofs with a non-breathable underlay. A bare garage with open rafters breathes by itself; it is the moment you add a ceiling that those rules start to matter.
Sheet-covered pitched garages and asbestos cement
Many older pitched garages in Gloucestershire carry corrugated sheet, and start by establishing what that sheet is. Cement-based corrugated sheets fitted in past decades may contain asbestos. You cannot tell by looking: the only reliable route is a laboratory test, and our answer on whether your garage roof is asbestos explains the steps.
HSE guidance puts careful removal of intact cement roof sheeting, weathered sheets included, in the non-licensed category. Badly damaged sheets, or a job that would shatter them into dust and debris, move it up to the notifiable tier and the enforcing authority must be told before it starts.
Do not drill, scrub or break it
Intact asbestos cement is stable. The risk comes from disturbing it. Pressure washing a moss-covered sheet, walking on a brittle one or drilling to fit a skylight are all ways to release fibres. If you suspect your sheets are cement, leave the roof alone and ask for a survey first.
Other sheet types
Corrugated bitumen sheets, fibre-cement sheets made without asbestos and steel panels are all found on pitched garages. Each fixes differently, and each tells a different story when it fails: bitumen sags and cracks, cement sheet moss over and snaps at the fixings, steel rusts from cut edges and screw heads. Our box-profile sheet guide goes deeper on the steel option, which is the usual replacement.
Faults we find on pitched garage roofs
Surveying a pitched garage, we climb from the ridge downwards through a short list of checks. Your own roof is photographed as we go, so the quote can point at the actual defects.
Slipped or cracked tiles
Tiles move when the nail has corroded or the batten beneath has softened. A slipped tile exposes the underlay or the bare batten, and the leak shows later, away from the gap. Replacing a few tiles is a small job; the question is why they moved. If it is nail failure across a whole slope, repairing tile by tile will chase the problem around the roof.
Failed ridge and verge mortar
Hairline cracks in the mortar let water in beside the ridge, and the loosened tiles are then at the mercy of the wind. Repointing a ridge or hip is quoted by MyBuilder in 2026 at £200 to £400.
Moss and lichen
Moss holds water against tile and slows drying. It is common on the shaded north slope of a garage under a tree. Hand scraping is kinder than a pressure washer, which can damage tiles and, on cement sheet, is best avoided entirely.
Rotten timbers
Rafter feet and wall plates are the first timbers to suffer when the gutter has overflowed for years onto the wall head. Soft, crumbling wood under the eaves means the guttering needs looking at along with the roof.
Dropped ridge line
A ridge that sags in the middle points to a structural problem: undersized timbers, a missing collar or a wall that has moved. That is not a repair job, and it is the sort of finding that makes us suggest a structural check before quoting for tiles.
Repair or replace: where the line falls
A garage roof earns a repair when the trouble sits in one place and the timbers hold firm. A handful of cracked tiles, a failed section of ridge or a lifted verge are all sensible repairs. Checkatrade's repair cost guide, last updated in June 2026, gives concrete tile repairs at £90 to £120 per m², and clay at £110 to £160 per m², excluding VAT and access; MyBuilder lists minor roof repairs at £100 to £300.
Replacement makes sense when a large part of the slope has slipped, the battens crumble when pressed, the underlay has perished, or the sheets have gone brittle across their whole area. Patching a failing roof means paying for access each time something new lets go. MyBuilder's garage roof guide shows £2,500 to £4,500 for a pitched garage roof, a typical UK range that moves with size, covering and access. It is not a Supreme price. Your figure follows the visit, as a written quote for the whole job.
A repair bill that is heading towards a third of the replacement cost, and only buys a few years, deserves a second look before you commit.
A word on overlaying
Fitting new sheets over old sheets is sometimes suggested for asbestos cement, and it has its place; our guide to overlaying asbestos roofs explains the limits. On a tiled roof, going over the top is not a sound option because of the weight and because it hides the timbers you need to check.
Replacing a pitched garage roof: weight, rules and workmanship
The job begins with the access, which on steep lanes and terraced back gardens is planned into the quote rather than found on the day. The old covering is lifted section by section, and every rafter, wall plate and batten is inspected as it is exposed. Anything soft is cut out and replaced. A new underlay goes down, new battens are fixed, and the covering follows.
Like for like, or lighter, or heavier
If the garage has concrete tiles, concrete tiles go back. A covering that makes the roof 15 per cent heavier or more needs Building Regulations approval, and the Planning Portal advises asking with a structural engineer or surveyor first. Fitting heavy tiles onto a frame built for sheet is the classic example. Going lighter is easier on the frame, but the new roof still needs proper fixings against uplift in wind.
Do you need approval?
Under the Planning Portal's thresholds, a building control application is not normally needed if under 25 per cent of the envelope and under 50 per cent of the roof is touched. A detached garage roof stripped in full can pass both figures. Where it does, we deal with the Building Regulations notification and explain whether insulation also comes into it. A like-for-like roof does not normally call for planning consent; still check with Stroud District Council's planning team if the garage is listed, forms part of a listed building's curtilage, or sits in a conservation area.
Finish and waste
The ridge is fixed mechanically, the verges are made weathertight, the gutters are checked for fall, and we leave the garden clear, with the old covering carted off. The work carries a 10-year workmanship guarantee, in writing.
Sheds, leaks and the neighbouring guides
Pitched sheds and workshops follow the same logic as garages, but with lighter timber and different coverings. Our guide to shed and outbuilding roofs covers felt, felt shingles, EPDM and sheet for those smaller buildings.
If the reason you are reading this is a stain on the garage ceiling, remember that the wet patch is rarely directly under the hole. Water runs along the rafter or the underside of a sheet and drops where it finds a low point. A pitched roof usually tells you which slope is at fault: look for the side that gets the weather. Fix the real cause first, whether it is a flashing at the house wall, a tile row or a dripping gutter, and then see what the ceiling does.
Before you ring
- Note whether the covering is tile, cement sheet or metal.
- Take photographs from the ground, in daylight, of each slope and the ridge.
- Check inside for daylight through the roof, damp timber and stained walls.
- Look at the gutters and downpipes for overflow marks.
- Leave sheet roofs alone until you know whether they contain asbestos.
Photographs sent by WhatsApp or through the form, or a call on 01453 933613, let us say what the survey needs to look at first.