Most garage roof replacements don’t drag on for weeks. In many cases, a single garage roof can be replaced in one day, and a double garage often takes one to two days — but the exact timescale depends on the roof type, materials, access, and whether any hidden timber/decking repairs are needed.
This guide explains realistic UK timeframes, what slows the job down, and how to plan so you’re not caught out.
Typical timeframes (at a glance)
Here are the time estimates homeowners usually want first.
How long it takes (guide)
| Garage roof type | Single garage | Double garage |
|---|---|---|
| Flat roof replacement (felt / EPDM / GRP) | 1 day | 1–2 days |
| Corrugated sheet replacement (steel/bitumen/cement style) | 1 day | 1–2 days |
| Pitched roof replacement (tiles/slates) | 2–4 days | 3–6 days |
These are typical working times, assuming reasonable access and weather.
Why flat garage roofs are usually quicker
Flat garage roof replacements often involve:
- removing the old covering (or preparing it)
- checking the deck/timbers
- fitting the new system (felt/EPDM/GRP)
- finishing edges, corners, and outlets
Because the roof area is relatively small and access is often simpler than a house roof, a lot of jobs are completed within a day.
Example “one-day flat roof” schedule
| Stage | Typical time |
|---|---|
| Remove old covering / prep | Morning |
| Inspect deck + minor repairs | Late morning |
| Install new roof system | Afternoon |
| Edge trims + outlet detail | Late afternoon |
| Clear up / waste removal | End of day |
The biggest factor: is the decking/timber sound?
This is what turns a “quick job” into a longer one.
Signs you might need decking or timber repairs
- the roof feels soft underfoot (don’t walk on it—just note any sagging)
- you can see sagging from inside the garage
- leaks have been happening for a long time
- there’s visible staining, damp, or mould on internal timbers
How much time can deck repairs add?
| Repair type | Extra time (typical) |
|---|---|
| Minor local deck repair | +1–3 hours |
| Significant deck replacement | +½ to +1 day |
| Structural timber repairs | +1 day or more (depends on extent) |
Material choice can affect time
Some systems are quicker to install than others, and drying/curing time matters.
Material timing notes
| Material | Timing considerations |
|---|---|
| Felt (modern systems) | Often installed in a day; detailing matters |
| EPDM | Often efficient to fit; edges and terminations are key |
| GRP | Can be a quick install but needs correct curing conditions for best results |
| Corrugated sheets | Often quick, but time depends on fixings, overlaps and detailing |
| Tiles/slates (pitched) | Slower due to battens, underlay, tile laying and detailing |
What else can slow it down?
1) Weather
- High winds make sheet handling and edge work harder
- Persistent rain can delay certain steps
- Cold conditions can affect some adhesives/resins
2) Access and safety setup
- tight driveways
- attached garages with junction work
- limited working room or obstacles
- need for scaffold/tower (less common for garages, but sometimes needed)
3) Waste removal logistics
If the old roof is bulky (or has multiple layers), removing and disposing of waste can add time. Sometimes a skip hire is needed.
4) Junction and flashing complexity (attached garages)
Where the roof meets the house wall often needs careful detailing, which can add time but is worth it to prevent recurring leaks.
What about asbestos garage roofs?
If your garage has older corrugated cement sheets that may contain asbestos, the job can take longer because asbestos removal and disposal need controlled handling and the correct process. This doesn’t always mean it takes “days”, but it can add steps and scheduling.
Tip: If you suspect asbestos, mention it in the quote request so you’re not delayed on the day.
Can you use the garage during the work?
Usually you’ll need to clear the area near the roof edges and keep the space safe.
Practical planning tips
- Move items away from walls and roof edges inside the garage
- Keep vehicles out of the driveway if roofers need access
- Expect noise and dust during removal
- Don’t plan to store valuables in the garage during the work
How to speed up the job (without cutting corners)
You can make the replacement smoother by doing a bit of prep:
Homeowner prep checklist
- Clear the driveway for access and materials
- Clear the garage edges inside (especially if water has been leaking)
- Take a couple of photos of the roof and leak areas for the quote request
- Tell the roofer about: ponding water, junction leaks, gutter overflow, soft/sagging areas
What to include in your quote request (copy/paste)
- Postcode
- Single or double garage (or rough length × width)
- Roof type (flat felt / EPDM / GRP / corrugated / pitched tiles)
- Any known issues: leaks, ponding water, lifted edges, sagging
- Whether the garage is attached to the house
- Access notes (tight driveway, height issues, obstacles)
- Ask: “How long do you expect the job to take?”
FAQs
Can a garage roof replacement really be done in one day?
Often yes, especially for flat roofs or corrugated sheet roofs on a single garage with good access and minimal decking repairs.
What makes a garage roof replacement take longer?
Hidden deck/timber repairs, poor access, bad weather, complex wall junction/flashing details, and waste removal can all add time.
How long does a pitched garage roof replacement take?
Pitched roofs typically take longer than flat roofs because there are more components and more laying/detailing work. A common range is 2–4 days for a single garage and 3–6 days for a double.
Should I clear my garage before the work?
It’s a good idea to move items away from walls and roof edges and to clear the driveway for access. It helps keep the work area safe and can speed things up.
