Flat roofing in Post Green

The garage. Most of what we do here. 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 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.

No rate per square metre, because the square metres are the easy part and what is under the covering is what decides the job.

Getting to it. A detached garage down a shared drive, a link roof joining a bungalow to its garage and a full width rear extension are three different jobs before a sheet comes off. A garage or a single storey extension will often come off a tower, anything above a two storey wall wants a scaffold, and the platform has to stand while the deck is open rather than for an afternoon. The work at height rules are why it is a priced line rather than something folded into a rate.

The deck under the covering. A sound deck can be re-covered. Chipboard that has been wet for years, or ply that gives underfoot, has to come off and be replaced, and you cannot tell which you have from the ground or from a photograph. We lift a corner before quoting, because the deck is the single biggest swing in the price.

The falls, and where the water is meant to go. Most flat roofs that fail were never laid to a fall, or the fall runs at an outlet that has since been blocked or built over. Correcting it with firrings is more work than laying a membrane and it is the difference between a roof that lasts and one that ponds. Upstands, edge trims and each outlet are priced one at a time, because that is where the hours and the leaks both are.

Comparing quotes? Ask which system is being quoted and how many layers, whether the deck is being renewed or covered over, whether the falls are being corrected with firrings, how the upstands, outlets and edge trims are detailed, and whether the scaffold and the skip are in the price. Two quotes for the same job are usually two different jobs.

We cover Post Green, Lytchett Minster, Upton, Lytchett Matravers and the BH16 side of Poole, and the site visit costs you nothing. You are dealing with Bournemouth Roofing & Building, the trading name of Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719, which you can look up in a minute. Thomas Hannen's business, and he is the one who comes out to price the job, not a salesman. A verified customer's 10 out of 10 on Checkatrade. The visit and the written quote are both free.