Flat roof replacement in Canterbury costs £1,200–£6,000 depending on size and system. GRP fibreglass and EPDM rubber both carry 25-year-plus guarantees and are the two systems worth fitting — we don't recommend felt as a replacement because it fails within 10–20 years. GRP suits complex shapes; EPDM suits large simple roofs.
What Does Flat Roof Replacement Cost in Canterbury?
Replacing a flat roof in Canterbury costs £1,200–£6,000, driven by the roof's size, the system chosen, and whether the timber deck underneath needs replacing. A single garage roof sits at the lower end; a large extension or a wet, rotten deck needing full replacement at the upper end. The figure includes stripping the old covering, repairing or renewing the deck, and fitting the new system with proper falls to drain.
BS 6229 covers the design and installation of flat roofs with continuously supported coverings, setting out falls, drainage and detailing that a compliant flat roof replacement must follow.
Source: BS 6229 (flat roofs with continuously supported flexible waterproof coverings)
GRP or EPDM — Which Is Right?
Both are excellent, and both beat felt hands down. GRP fibreglass is applied as a liquid and cures into a hard, seamless shell — ideal for complex Canterbury extension roofs with upstands, trims and multiple angles. EPDM rubber is laid as a single large sheet, which makes it cost-effective and quick on big, simple rectangles like a garage or outbuilding. GRP gives a firmer finish; EPDM flexes better in cold. We recommend whichever fits your roof's shape and use.
Why We Don't Fit Felt
Traditional built-up felt is what most failing Canterbury flat roofs are covered in — and it's why they're failing. Felt has a design life of just 10–20 years, it goes brittle and cracks in sun and frost, and its seams are weak points. Replacing a failed felt roof with more felt just restarts the same short clock. For a modest amount more, GRP or EPDM lasts more than twice as long, which is why we fit those instead.
How Long Does a Flat Roof Replacement Last?
A properly-installed GRP or EPDM flat roof in Canterbury lasts 25–35 years, and both come with a substantial guarantee. The main thing that shortens a flat roof's life is standing water from inadequate falls, so we make sure the new roof drains properly rather than ponding — a detail that cheaper installations often get wrong.
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