The short answer
Yes. We replace roofs on attached garages, whether flat, pitched or a lean-to. The covering is the simple part. The care goes into the abutment, the joint where the garage roof meets your house wall, and into the flashing that seals it. Because the garage shares a wall with your home, it is also sensible to ask building control about fire performance before you choose a new covering.
A garage that touches the house needs more thought than a detached one. The roof edge against the wall is where most of the skill sits.
Where the garage roof meets the house wall
On an attached garage the roof ends against a wall of the house. Roofers call that joint the abutment. Rain runs down the house wall, lands on the garage roof and tries to get behind the covering, so the joint is sealed with a flashing, a strip of metal that is tucked into the brickwork and laid over the roof edge.
What happens to the old flashing?
It comes off first, and the wall behind it is looked at before anything new goes on. Crumbling mortar, a cracked render band or a loose brick will let water in however good the new flashing is. The slot the metal sits in, called a chase, is cut into a mortar joint and the top edge is dressed in tight, then sealed.
Lead is the usual metal. Royston's cast-lead brochure lists code 4 to code 6 for flashings, and code 4 is 1.80 mm thick. Which thickness suits your wall depends on how long the flashing runs and how exposed it is, and the survey settles that. Where the roof is pitched, the lead is stepped to follow the brick courses. On a flat garage roof the membrane turns up the wall as an upstand, the upturned edge, and the flashing covers the top of it.
Fire performance and the shared wall
A garage that is joined to the house puts a roof covering close to a living space. That is why a change of material is worth a conversation with building control before work begins.
Does a new garage roof need Building Regulations approval?
The Planning Portal lists two triggers for approval. One is a covering at least 15 per cent heavier than what it replaces. The other is a finish that would react to fire quite differently from the existing one. Laying felt where felt was before is a different question from moving to a heavier tile or another membrane.
The Planning Portal also gives a yardstick for when no application is needed: under 25 per cent of the building envelope affected, and under 50 per cent of the roof. Somerset Building Control lists no re-roofing percentage, so describe your job against the Planning Portal wording. Ring 0300 303 7790 with the garage, the covering you have now and the one you want. On weight, the Planning Portal recommends that a structural engineer or surveyor checks first.
What we find at the survey goes into the quote, so the answer from building control lines up with the roof we price.
Flat, pitched or lean-to: choosing the covering
Attached garages come in three common shapes. A flat roof sits level with a slight fall, a lean-to slopes away from the house wall, and a pitched roof has two slopes that meet at a peak, which roofers call the ridge.
What fall does a flat garage roof need?
BS 6229:2025 keeps a minimum finished fall of 1:80, and IKO advises designing for 1:40 so that settlement and tolerances do not leave puddles. A garage roof that ponds shortens the life of any membrane.
Typical lives, as published, are 10 to 20 years for torch-on felt, 25 to 40 for GRP (glass-reinforced plastic) and 30 to 50 for EPDM, a rubber membrane (Less, Oct 2026). GreenSpec puts EPDM at 20 to 30 years, so the sources disagree, and none of these is a promise. MyJobQuote's guide puts a garage roof at £750 to £3,500 as a typical UK range, averaging £1,500 (Oct 2026). Size, access and the covering move you around inside that range.
A lean-to or pitched garage can take tiles or sheets, and we check the pitch against the maker's minimum before suggesting either.
Water inside the house and how we trace it
People often notice trouble from indoors: a brown stain on the utility room ceiling, damp on the house wall above the garage door, or peeling paint where the two buildings meet. Those marks can come from the abutment, but they can also come from a blocked gutter, a cracked wall or condensation.
Is a damp patch at the wall always the flashing?
No. Before we price a replacement we look at the whole line: the flashing, the mortar above it, the gutter beside it and the downpipe. A gutter that overflows onto the wall can mimic a failed abutment, and a cheap fix at the right place beats a new roof at the wrong one.
Access matters on an attached garage too. The house wall, a boundary fence or a neighbour's side passage can limit where ladders and a scaffold tower stand, and we plan that before the day starts. Waste leaves with us, and the house side is kept clean.
You can see how we deal with leaks in general in our guide to a leaking garage roof, and the cost side is on the garage roof cost page. Our garage and asbestos roofs page covers the wider service. Book the survey with the wall in mind: we photograph the abutment up close and put the price for it in writing.
More on joined garages
Will replacing the garage roof disturb my house roof?
Only at the meeting point. The garage covering is lifted back to the wall, and the flashing is renewed, but the house slates or tiles above it are left alone unless the survey shows they have been damaged by water running down the wall.
Can the garage and house share one gutter?
Sometimes, when the garage roof drains toward the house gutter or a shared downpipe. We check the outlet size and the fall during the survey, because adding a garage roof's water to an undersized gutter can make it overflow in heavy rain.
The full picture: Garage and asbestos roof replacement in Taunton · More short answers