Choosing a garage roof covering is mostly a matter of matching the material to the roof you have. A flat deck wants a membrane, a low-pitched frame built for cement sheets wants profiled sheeting, and a proper pitched roof can take tiles. Cost and life pull in different directions: a low price at the start can cost more across twenty years, and the longest-lived covering may not suit a small roof with awkward edges. This guide sets out the four coverings most garages end up with, using typical UK cost figures and lifespans from published sources, and explains where each one earns its place. Lifespans are ranges that depend on exposure, workmanship and upkeep, never promises. Your own roof gets a firm answer after a survey.
Start with the deck, the pitch and the edges
The covering is the last decision, not the first. Three facts about the garage narrow the field before price comes into it.
The first is the pitch. A roof that falls less than a few degrees is, in effect, flat, and it needs a continuous membrane with no open laps that water can be driven through. A roof with a steeper slope can take overlapping sheets or tiles, because water runs off before it can creep sideways. Tiles and slates each have a minimum pitch, and a frame built to a shallow slope cannot simply be tiled over.
The second is the deck. A flat roof carries its membrane on boarding, and a boarded deck must be dry, flat and fixed down. A roof of sheets has no deck at all: the sheets span the purlins, the horizontal timbers between the walls, and that sets the load limit on what can replace them. Cement sheeting is heavy, and a lighter covering asks less of old timbers.
The third is the edges. A garage roof has a small area and a long perimeter in proportion, so the finish at the gutter, the verge and the abutment with the house wall matters more than on a large roof. A material that is easy to detail neatly at corners and upstands earns points for that alone. Water that drains off quickly does less harm, and manufacturers working to BS 6229:2018 design for 1:40 so the finished fall is no worse than 1:80.
With those three facts in hand, the sections below take each covering in turn. Each figure is a typical UK range from a named source.
Bitumen felt: the traditional flat roof covering
Felt is the oldest of the four and still common on garages. Modern felt roofing is made from bitumen reinforced with polyester, built up in layers, and torch-on felt is the version where the underside of each sheet is heated with a flame to fuse it to the layer below. MyBuilder's flat roof cost guide (2026) puts felt at a typical UK £70 to £100 per m², the lowest of the membranes here.
Its weakness is its life and its seams. Published figures vary: a trade source gives 10 to 20 years for torch-on felt, while others allow up to 30 years for a good multi-layer system with a protective top layer. One cost guide sums it up well, that a good felt job can last 20 years where a poor one might fail in under 10. Quality here means the number of layers, the standard of the laps and the surface finish, such as mineral chippings or a solar-reflective coat, which shields the bitumen from sun and frost.
The flame is the other consideration. A naked flame near a timber deck, a boundary fence or the underside of an eaves is a fire risk that the roofer has to control. On a garage attached to a house, or next to a neighbour's fence, many owners prefer a method that avoids a flame, and felt systems that are self-adhesive or cold-applied exist for that reason.
Felt suits a garage where the budget is tight, the roof is simple and the owner accepts a shorter cycle. It is a weaker choice where the roof will be hard to reach again, or where a cut or blister in the surface will be hard to spot. Repairs to felt are straightforward when the cause is found, and patching a split can add useful years. The judgement is set out on our repair or replace a garage roof page.
EPDM: a rubber membrane in one piece
EPDM is a synthetic rubber, and on a flat roof it arrives as one large sheet cut to the roof's size. That MyBuilder guide lists EPDM at £90 to £130 per m², a typical UK range. Sources differ on its life: 20 to 30 years or more is the safest way to put it, with some figures higher, and manufacturers' own guarantees commonly sit at 20 to 25 years. A guarantee is not a lifespan, though, and the two should not be confused.
What EPDM offers a garage is a single sheet with no joins in the middle. On a small roof the membrane often covers the whole slope in one piece, and joins are where membranes most often fail. The sheet is stuck to the deck with adhesive, or laid loose and ballasted, and the edges are finished with trims. It is flexible in cold weather, so it copes with the movement of an old deck better than a rigid skin does.
Where EPDM can disappoint is at the details. It performs only as well as its folds and fixings at the corners, around pipes and up the wall against the house. Those details use separate pieces and adhesive tapes, and they need clean, dry surfaces and a roofer who has done it before. A roof punctured by a falling branch or a ladder can be repaired, but the patch has to be made with the right materials.
EPDM is a strong choice for a garage with a plain rectangular roof, a sound deck and sensible access. It gives a long life for a mid-range price, and it keeps its looks in a plain dark finish. It is a weaker one where the roof has many penetrations and tight corners, since each is a hand-made detail.
GRP: fibreglass laid wet
The letters GRP stand for glass-reinforced plastic: a fibreglass laminate built up on the roof from resin and glass matting, under a topcoat. It cures into one hard shell without a single join, which is its main selling point. MyBuilder's flat roof guide (2026) gives a typical UK £95 to £150 per m², the highest of the three membranes, and published lifespans run from about 25 to 40 years when it is well installed and maintained.
The way GRP behaves is different from a rubber sheet. It is rigid, so it needs a firm, stable deck, because movement in the boards can crack the skin. It is laid in a single operation on a dry deck in suitable weather, and damp or cold at the wrong moment can ruin the cure. The finish is smooth and can be taken up a wall and round an edge in one go, which makes it good for awkward shapes, odd corners and small roofs with many details.
For that reason a GRP roof is often chosen for a garage with a complicated plan, or where there will be foot traffic on the roof, since the surface is tough. A GRP roof can also be coloured to match a house or a fascia. The same hard surface can be a weakness if a deck moves: a hairline crack lets water in, and it can be hard to trace. Repairs are possible with fresh resin and matting, though the colour may not match the old topcoat exactly.
GRP is the choice when the deck is sound and stable, the roof shape is awkward, and a joint-free finish is worth the higher price. Choose something more forgiving where the timbers are old and moving. That call is made on the roof, not from a catalogue.
Profiled sheeting and tiles for pitched garages
A garage roofed in corrugated cement sheets, whether or not they contain asbestos, was built with a frame designed to carry a light, overlapping sheet. Profiled metal sheeting, normally coated steel, is the nearest modern match. It spans the purlins, it is light, and it can be fixed quickly. Sources for the life of metal sheeting vary widely, from 40 to 70 years in one cost guide and more than 50 in a trade body's note, with one supplier quoting 15 to 25 years to first maintenance for a coated steel sheet. Exposure, coating and maintenance explain the spread.
The detail to check is condensation. Metal sheeting is thin and cold, and a garage with a car or damp items inside can drip from the underside on a cold morning. An anti-condensation backing or lining fixes that, and it is worth asking whether the sheet you are quoted has one. Fixings must be correct for the sheet and sealed, as the fixing holes are the most likely place for a leak.
Where the garage has an asbestos cement roof, sheeting is a common replacement because the existing purlins already match its spacing, and the weight is far less. The removal of the old cement comes first, and we describe how that is done on our page about asbestos garage roofs.
A pitched garage with a pitch steep enough for tiles can be covered with concrete, clay or slate, though the structure has to be able to carry the extra weight. Typical lives from published sources are 30 to 50 years for concrete interlocking tiles and 40 to 60 for clay plain tiles, with long-lived natural slate above that. The cost and method sit on the pitched garage roof page. Sheeting costs are not given per square metre in the sources we use, so a measured quote is the only reliable figure.
Putting the four side by side
Figures in the table are typical UK ranges, each from a source named above. The costs are for a flat roof covering per m² from MyBuilder's flat roof guide (2026), and the lives are the ranges published by trade and supplier sources, which are not guarantees.
| Covering | Typical UK cost per m² | Typical life |
|---|---|---|
| Bitumen felt | £70 to £100 | 10 to 20 years, more for a good multi-layer system |
| EPDM | £90 to £130 | 20 to 30 years or more |
| GRP | £95 to £150 | 25 to 40 years |
| Profiled metal sheeting | Priced on measure | Wide published range, 40 years or more overall |
A modest covering on a sound deck can outlast a dear one on rotten boards, and the figures say nothing about the deck. Your fixed quote follows the survey.
As a rough guide, felt suits the tightest budget on a simple roof, EPDM suits a plain rectangle with a sound deck, GRP suits awkward shapes on a stable deck, and sheeting suits a low-pitched garage built for it. There are exceptions. A roof with a lot of lead already around it may stay in lead, which MyBuilder's guide puts at £150 to £200 or more per m², though that is rare on a garage.
A survey settles what the guides cannot. On site we peel back a corner of the old covering, test the deck, measure the falls and take photographs of your roof. Our written fixed price follows, for the material we recommend and with the reasons for it. If the garage sits under trees, say so, as leaf fall and shade favour some coverings over others. Where the existing roof can be mended, that is the first thing you hear. For the money side, see our garage roof cost guide, and for the full service, garage roof replacement.