Felt garage roof costs area times the installed allowance plus confirmed extras and tax; the default example is about £1,550.
Start with the garage you actually have
Measure the roof instead of assuming every single garage or double garage has a standard footprint. The default is an illustrative 6 m by 3 m rectangle, not a garage-size rule. Roof overhangs should be included in those dimensions. A flat roof uses zero pitch; a pent or pitched garage uses the angle to convert footprint into covering area. Irregular adjoining carports and separate lean-tos need additional measurements.
Felt, EPDM and GRP are available here because comparable installed membrane prices were verified. Corrugated metal and fibre-cement systems need a supplier quote and have not been assigned invented premiums. Deck replacement and access costs are entered as confirmed additional amounts. Inspect the underside as well as the covering: leaks can damage boards or roof members long before the visible surface looks beyond repair.
Example: an 18 m² felt garage roof
The default net felt range is £54.17 / £72.08 / £90 per m². Eighteen square metres at the midpoint comes to £1,297.44. VAT of £259.49 gives a total of £1,556.93, displayed as approximately £1,550. The penny figure rounds the underlying £1,556.928 total to two decimal places. Removal, deck repairs, access and asbestos work are excluded in this example; their quote fields are zero.
Reference installation allowances
| Garage membrane | Checkatrade GBP/m² before VAT | MyBuilder GBP/m², tax basis unspecified |
|---|---|---|
| Felt / bitumen | £50–80 | £70–100 |
| EPDM rubber | £80–100 | £90–130 |
| GRP fibreglass | £95–120 | £95–150 |
Sources read 1 October 2026: Checkatrade flat replacement costs and MyBuilder membrane roof costs. These are membrane allowances applied to the measured garage surface. They are not asbestos-removal prices. The calculator permits either tax interpretation where a guide is unclear, blends the resulting net endpoints, and adds standard VAT separately.
Asbestos garage roof replacement cost
Old corrugated sheets may contain asbestos cement, but appearance alone cannot identify it. Select suspected asbestos to reveal the safety note and obtain a professional survey or assessment before disturbing the sheets. The estimate does not infer a removal category from the garage area. Enter the professional removal and disposal quote only after its scope is clear.
HSE guidance on non-licensed and notifiable work distinguishes material type, condition and the method of work. Asbestos cement can fall under non-licensed work in suitable circumstances; substantial damage or deterioration changes the assessment and notification requirements. A calculator cannot turn that distinction into a safe homeowner removal instruction. Keep survey, removal, waste handling and the new roof contract clear when comparing quotes.
Also ask whether the garage is attached, whether stored items need protection and whether the access arrangement affects the neighbour's property. Temporary weather protection and disposal documentation may be part of the contractor's scope, even when neither appears as an independent unit rate in a price guide.
Finish the outbuilding plan
For a heated extension and insulation details, use the flat roof replacement cost calculator UK. Compare the UK roof replacement cost calculator for the house, check a glazed addition with the conservatory roof replacement cost calculator, and confirm the slope using the roof pitch calculator.