The short answer
For a single garage with a sound frame, a replacement covering is often a matter of a day or two. A double garage, a roof needing timber repairs, or a conversion from flat to pitched takes longer. Asbestos cement roofs add time for assessment, careful removal and waste disposal. Weather can pause work, since the roof is open while the old covering is off.
What the job involves
A garage re-roof starts with access. Scaffold or a tower is set up, and the garage contents are protected or moved. The old covering is stripped, and the frame or deck beneath is inspected. Rotten timbers, sagging purlins or a weak deck are repaired. The new covering is then laid, with edge trims, flashings, ridge pieces and gutters fitted. Finally the site is cleaned and the old material taken away.
Each step takes time, and the length of the job is mostly set by what is found when the old roof comes off. A roof that looked fine from the drive may hide wet boards. That is why a quote based on a survey states the work that is known and says what may change.
The covering makes a difference
A flat roof in rubber can go on quickly, because a large sheet is laid in one go. Felt takes longer, with layers to lap and seal. Fibreglass needs each stage to cure before the next, so the weather matters. Metal or fibre-cement sheets on a pitched frame go on fast if the frame is true, but each sheet has to be fixed and the ridge and flashings dressed. Tiles take longest, since each is laid on battens. Our guide to garage roof materials compares them.
If you are weighing a flat garage roof, our page on whether EPDM is good for a garage roof explains why rubber is quick and low-maintenance.
When asbestos is involved
An asbestos cement roof adds steps. First, the material has to be identified, and a sample may be sent for analysis, which takes a few days. The work then follows a risk assessment, with controls and trained workers. HSE treats careful whole-sheet removal as non-licensed, while a plan to smash the roof up moves the job into the notifiable group. The sheets are wrapped, labelled and taken to a suitable site. Allow extra time for all of this. Our guide to asbestos garage roof removal sets out the process.
Other things that add time
A flat-to-pitched conversion is a build, not a re-cover, and takes much longer; see flat to pitched garage roofs. Concrete sectional roofs may need panels replaced or reinforced. A garage attached to the house has flashings and a party wall to detail. Poor access, with no room for a ladder, tower or deliveries, slows everything.
Weather matters. The roof is open once the old covering is off, so crews strip only what they can cover that day. A wet or windy spell can pause work. Felt and resin coverings need dry surfaces. Building Regulations inspections, where they apply, must also be booked. Our guide to garage roof planning permission explains when approvals come into it.
A typical sequence of days
On a straightforward single garage, the first day is usually access, stripping and any quick timber repairs, with the roof made watertight by the evening. The second day lays the covering and finishes edges, flashings and gutters. A third day might be needed for cleaning up, a ridge or a detail that waited on a delivery or a dry spell. Larger garages repeat this across more area, and an asbestos roof begins with an assessment visit and may include a separate day for removal before the new roof is built. Treat the order as a guide, because the roof you have decides the real programme.
Why quoted times shift
No honest roofer can promise an exact schedule before the old roof is off. Rotten timber, a hidden second layer, a drain that needs rerouting or a delivery that is late can each add time, and the weather decides the rest. We prefer to give you a range and tell you early when something changes. If the frame needs more work than expected, we show you the photographs and agree the change before going on, so there are no surprises on the bill.
How to prepare
Clear the garage of anything that dust or debris could spoil, or cover it. Move cars off the drive so the crew can unload. Let neighbours know there will be noise and a skip or scaffold. Make sure there is a power point and access to the roof. If the garage is full, tell us at the survey so we can plan around it.
Our programme
The free survey includes photographs of your garage roof and frame, and we give a realistic range for the time, with the points that could change it. The fixed written quote names the work, and we leave the garage swept and the old material gone. A written ten-year workmanship guarantee comes with the new roof. See garage roof replacement for the options.
Every roof is different. A free survey with photos settles it for yours.
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