Garage, outbuilding & workshop re-roofing
In short
Detached garages, workshops and stores get the same treatment as a house roof at a fraction of the cost — and they are usually decades overdue. The two things to establish first are what the existing covering is, and what the structure will carry.
Also called: Garage re-roof · Shed roof replacement · Workshop roof · Outbuilding roof replacement
Signs you need this
- Water getting into a garage, workshop or store
- Old felt that has blistered, split or gone chalky
- Grey corrugated cement sheeting from before the mid-1980s
- Rusted-through corrugated steel
- A sagging or springy deck
- No guttering, or a gutter discharging against the wall
Outbuilding roofs are the most neglected coverings on any property, for the understandable reason that nobody sleeps under them. They are also the cheapest to put right properly, because they are small, low, and usually accessible without a full scaffold.
The first question is always what is on there. Felt on a flat deck is the commonest and the simplest — strip, check the deck, form falls, re-cover in EPDM or a modern high-performance system. Corrugated steel or bitumen sheet on a pitched frame is quick to replace and appropriate for a store or workshop. Tiled or slated outbuilding roofs are small versions of house roofs and get the same approach.
Corrugated cement sheet is the one that changes the job. If it went on before the mid-1980s it very likely contains asbestos, and work on it is controlled by the Control of Asbestos Regulations 2012. Asbestos cement is normally non-licensed work — a trained contractor can remove it without an HSE licence — but it must never be broken up, cut with a power tool or dropped from the roof, and it has to go to a licensed waste site with a consignment note. Sheets come off whole, wrapped, and go properly. Where there is genuine doubt about what it is, it gets sampled rather than guessed at.
The structure is the second question, and it is easy to get wrong on a small building. Garages and outbuildings are lightly framed, and some older prefabricated concrete garages in particular have very limited capacity. Putting a heavier covering on than the frame was designed for is a real mistake — which is why a tiled finish is not automatically available on a structure that currently carries a sheet, and why the frame gets looked at before the covering is chosen.
Falls are worth the same attention as on the house. A flat outbuilding roof laid dead level ponds within a year, and standing water finishes a covering early regardless of what it is made of. Firrings on the deck to create a real fall add very little to the cost of a small roof and add years to the covering.
Rainwater is the part that gets forgotten. An outbuilding with no gutter, or with one that discharges against the wall, soaks its own footings and the ground around it — which then shows up as damp in whatever is stored inside. Sorting a gutter and a discharge point while the roof is being done is trivial in cost and makes a noticeable difference.
What the job covers
- Existing covering identified — including asbestos assessment
- Structure checked for what it will carry before the covering is chosen
- Strip back, deck and frame inspected, rotten timber replaced
- Proper falls formed rather than re-covering a level deck
- Asbestos cement removed under the 2012 Regulations and disposed of correctly
- Guttering and a proper discharge point fitted
What it costs
We don't publish a price for this yet, because a number pulled out of the air is worse than no number at all — your roofer has to honour it. On roofing it would also be close to meaningless: access is often the biggest single factor, and it varies enormously house to house. You'll get a firm price for your actual job when they ring you back, before any work starts. The quote itself is free and there's no obligation either way.
Common questions
Is my garage roof asbestos?
If it is grey corrugated cement sheeting and it went on before the mid-1980s, very probably. Modern fibre cement looks much the same and is not. Where anybody is going to disturb it, the answer comes from a sample and a test rather than a look from the ground — it is a cheap test and it changes how the job is done.
Can I put a tiled roof on my flat garage?
Only if the structure will take the weight and a pitched frame can be built over the existing one — which is a construction job rather than a covering change. On a lightly-built or prefabricated concrete garage the structural answer may simply be no, and that is worth establishing before anyone gets attached to the idea.
Is it worth spending properly on an outbuilding?
Yes, because the gap between a cheap job and a proper one on a roof this size is small in money and large in years. Stripping to the deck, forming real falls and laying EPDM on a standard garage is not a big job — but re-covering over a rotten deck with no fall is money spent again within a few years.
Does it need Building Regulations approval?
Re-covering a detached garage or small outbuilding usually does not, though it depends on the size of the building and what it is used for. If the building is attached to the house, or it is habitable, or you are changing the structure rather than the covering, it is worth checking with Cheshire East Building Control first.
Need this doing in Macclesfield?
Tell us the job and it goes straight to our local roofer — one call back, usually the same day. Free quote, no obligation.