Flat roofing

A flat roof is not flat. It has a fall — usually somewhere between 1:40 and 1:80 — and if it does not, it is a pond with a lifespan. Most of the failed flat roofs we are called to in Walmley and Mere Green have no meaningful fall left in them, because the deck below has sagged or was never laid to a fall in the first place. Recovering a roof that does not drain just buys you a few dry years. We build the fall back in with firrings before anything goes on top.

For coverings we use GRP fibreglass or EPDM rubber depending on the roof. GRP goes on wet and cures into one continuous piece with no seams anywhere, which makes it excellent on complex shapes with upstands, corners and pipe penetrations — the fiddly bits where felt always failed. It wants a dry, warm-ish weekend to lay properly, so we watch the forecast rather than fight it. EPDM is a single sheet of rubber, cut and bonded, which makes it superb on a big simple rectangle like a garage — one piece, no joints in the field at all, and it stays flexible in the cold in a way felt never did.

Both will comfortably outlast the three-layer felt they replace, and neither is exotic or expensive any more. On a 1970s Walmley garage the honest conversation is usually about whether the deck is worth saving. Chipboard decks from that era are frequently soft, and putting a twenty-five-year covering on a deck with five years left is money set on fire. If the deck is going, we say so.

The other flat-roof job we get a lot of is the dormer — those 1980s flat-roofed dormers all over the post-war estates. They are small, awkward, full of upstands and cheek junctions, and they leak at the joints rather than in the middle. That is a fibreglass job, because a covering that cures in one piece has no joints to leak at.