EPDM Rubber Flat Roofs in Windsor & Berkshire

EPDM is a synthetic rubber membrane made for roofing. It comes in large sheets, so on most garage and extension roofs the whole main area is covered by one piece, with no seams across it at all. Fewer joints means fewer places for a flat roof to leak.

The reasons we recommend it so often:

• It stays flexible in heat and cold, so it moves with the building instead of cracking
• No naked flame: it is bonded with adhesive, not torched, which suits roofs close to timber, fascias or windows
• Long life: our new roof cost guide gives EPDM a lifespan of 30 to 50 years
• Low maintenance: a clean, smooth surface that sheds water and needs little more than the outlets keeping clear

It suits simple, rectangular roofs best: single and double garages, single-storey extensions and dormer tops. On a roof that doubles as a balcony, GRP is the stronger choice.

An EPDM sheet across the middle of a roof does not leak. When EPDM roofs fail, it is almost always at the edges: an upstand that was not taken high enough up the wall, a corner that was cut instead of folded, a trim not sealed, or an outlet bodged in with mastic.

So that is where we spend the time. Upstands are taken up the wall and finished under a flashing so water cannot get behind them. Corners are folded, not cut. Edge trims are fixed and sealed so wind cannot get under the membrane and lift it. Outlets and roof lights are detailed into the sheet with the correct fittings.

Just as with every flat roof we build, the deck comes first. A new deck with proper falls means no ponding, and no ponding means the membrane is not sitting under standing water all winter. Our Kingston flat roof, shown here, started with new plywood decking for exactly that reason.