A flat roof is leaking or ponding and you want to know the options and costs.
Flat roofs get a bad name they mostly do not deserve. The reason so many fail early is not the material — it is that they were laid without a proper fall, so water sits on them instead of running off. Standing water finds every weakness, freezes, expands, and works its way in.
A flat roof built with the fall designed in, a sound deck and a single continuous membrane will comfortably outlast the mortgage on a garage. Rebuilt properly, it is not a job you should be revisiting in five years.
Guide ranges for South Wales in 2026, supplied and fitted including strip-off and waste.
| Job | Typical price |
|---|---|
| Single garage, torch-on felt | £1,400 – £2,200 |
| Single garage, EPDM rubber | £1,800 – £2,800 |
| Single garage, GRP fibreglass | £2,000 – £3,200 |
| Kitchen or rear extension (approx 20m²) | £2,600 – £4,800 |
| Dormer roof | £1,200 – £2,400 |
| Porch or bay roof | £650 – £1,400 |
| Replacing a rotten deck | add £22 – £40 per m² |
Prices assume reasonable access and an existing deck in serviceable condition. We will not know how much boarding needs replacing until the old covering is off, so we quote that as a clear rate per square metre rather than a vague “we’ll see”.
Every roof is different. The only number that matters is the one on your written quote, and that costs you nothing — ring 029 2010 0576 or ask for a free survey.
For most garages and extensions we would put GRP first for durability and EPDM first if the roof has a lot of awkward detail or the weather will not allow GRP. Felt is the value option and, laid in three layers, still gives you twenty years. There is no single right answer — it depends on the roof, the access and the budget.
Sometimes, and we will say so if a patch is genuinely the sensible answer. But if the covering is past its life or the deck is wet, patching is buying a few months for a meaningful fraction of the cost of doing it properly.
It is not. Building regulations expect a minimum finished fall of 1:80, and in practice we design to about 1:60 so it still drains after any slight settlement. A truly level flat roof is a pond waiting to happen.
On GRP, comfortably. EPDM is fine for occasional access but is softer and can be punctured by grit underfoot. If you want a usable balcony or terrace, say so at the quote stage — it changes the build-up and it is far cheaper to design in than to add later.
A single garage is usually one to two days. An extension is two to three. GRP needs dry conditions to cure, so we watch the forecast and will move a date rather than lay it in the wet and hand you a roof that fails.
“Finding a truly reliable roofing contractor in Cardiff can be tough, but this team exceeded all expectations. They completed a full roof renovation for us, staying strictly within the agreed budget and timeframe without any hidden costs. The craftsmanship and overall finish are flawless. Honest, efficient, and highly skilled!”
Full roof renovation
“Absolute top-notch service from Quick Fit Roofing Solutions! We were dealing with a persistent roof leak that had been causing us endless worry. The team arrived promptly, quickly diagnosed the root cause, and repaired it with exceptional precision. Their professionalism and attention to detail were outstanding. If you are anywhere in South Wales and need roofing work done, I cannot recommend them enough!”
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Guttering & slate replacement
Based in St Mellons, working across the city, the Vale, Newport, the valleys and the surrounding areas.
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