Flat roofing in Post Green

The garage comes first. Most houses in Post Green have one. A felt roof of this age fails at a lap that has split, a blister lifted off the deck, a seam gone between two sheets, or a trim whose fixings have pulled.

Each of those is a cut out, a prime and a welded patch under a fresh cap sheet, and it is a morning's work. What we check before agreeing to it is the board underneath, because a garage roof that has begun to dip has a wet deck, and the dip then holds the water that caused it.

The link. The strip of flat roof joining a Post Green bungalow to its garage is the one that leaks most and gets looked at least. It has an upstand on both sides, a fall of almost nothing, and an outlet that is usually behind a downpipe nobody has cleared. GRP fibreglass is laid wet onto the deck and is the better answer where there is that much to form round. On a plain run, EPDM rubber gives you a single sheet with no joints across the field.

The extension. Larger, usually over a room, and the one where the build up decides whether you are happy in five years. A built up three layer torch on felt system is still a sound roof and single ply suits the wider spans, but the question that matters is warm or cold. PIR insulation above the deck with the vapour control layer under it keeps the dew point out of the timber and stops the condensation and interstitial damp that get reported as a leak. A ventilated cold roof is fine over a store. BS 6229 sets the standard.

Decks and falls, on all of them. Plywood, OSB or chipboard, and chipboard swells the first time water reaches it. Where a roof was laid level, firrings go over the joists or tapered insulation does the same job, so water gets to the rainwater outlet instead of standing. Ponding does not come through a sound covering, but it keeps grit and moss on the surface and it is where the first split shows. A bubble underfoot means the deck has gone.

And the detail work. A lead cover flashing dressed into a chase at the abutment, the drip and apron at the front edge, the kerb round a rooflight, a parapet, a coping and a cavity tray formed rather than sealed, and a collar round every skylight, lantern, Velux, hatch, soil pipe and vent pipe. The gutter, hopper and downpipe are cleared and run through, because a good share of reported roof leaks are exactly that. A garage is a day, an extension with a new deck two or three working days.

The deck comes first. A Post Green garage or link roof from the seventies was usually decked in chipboard, and chipboard that has taken water swells and crumbles. Sound ply or boards can be re-covered; soft chipboard has to come off and be replaced. That is the biggest variable, and why the deck is checked first.

Warm roof or not. Over an unheated garage the insulation question hardly arises. Over a kitchen extension or a dormer bedroom, renewing the covering means insulation boards on top of the deck to meet Part L, which raises the roof edge, the upstands and every trim.

Falls and the outlet. A lot of link roofs in Post Green were laid dead flat, or drain into a gutter on the bungalow that is now blocked. Firrings to put a fall in, and a new outlet, cost more than the membrane itself. Each upstand against a wall needs a lead or membrane flashing chased in.

Access. A garage beside the drive is a tower job. A dormer on a chalet bungalow means scaffold round the main roof. The work at height rules set that, and it is priced as its own line.

Before you choose, ask any other quote which membrane and how many layers, whether the deck is being replaced or overlaid, and whether the falls are being corrected with firrings.

Post Green is about nine and a half miles from Boscombe, where our base is. We cover it along with Lytchett Minster, Upton, Lytchett Matravers and the BH16 side of Poole, where the council for planning and building control is Dorset.

The company is Bournemouth Roofing & Building Ltd, number 15471719, registered in England and Wales. Its owner, Thomas Hannen, climbs up to check the deck and prices your roof himself. On Checkatrade a verified customer marked us 10 out of 10. The site visit costs nothing and neither does the written, itemised quote. Before you book a visit in Post Green, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Post Green need no application at all. What decides whether a change to the outside of your house does is who the council is, whether a conservation area or a listing applies, and whether the place sits in a protected landscape.