Flat roofing in Swanage

Where the roof meets the stone. This is the detail that decides a flat roof in this town. The upstand is turned up, and the cover flashing is lead, worked into the coursing rather than run as a straight chase across the face of a stone. Where the beds are too irregular for that, the flashing steps with the joints, or a secret gutter is formed behind the abutment. Sealant along the top of an upstand is not a detail, it is a delay, and on a solid absorbent wall it puts the water inside rather than outside.

The covering, repaired. Where only one thing has gone we cut it out rather than strip the roof: a split at a lap, a blister lifted off the deck, a seam failed between two sheets, a trim whose fixings have pulled. Felt is primed and welded back under a fresh cap sheet, GRP fibreglass is ground out at the crack and re-laminated, EPDM rubber is cleaned and bonded down. On a small back roof that is a morning.

The covering, renewed. When the whole surface has hardened, EPDM rubber gives one sheet with no joints across the field, GRP fibreglass is formed in place where there is a kerb, an outlet or a rooflight, a built up three layer torch on felt system still suits many of these back additions, and single ply belongs over a shop's ground floor. An old lead roof behind a parapet that is still sound gets left alone, and we will tell you so.

The deck, the fall and the parapet. A Victorian addition often has plain boarding across the joists rather than plywood, OSB or chipboard, laid almost level. Firrings over the joists, or tapered insulation in a warm roof, get water to the rainwater outlet again. Ponding keeps the covering cold and wet under grit and moss, and standing water in one corner says the fall and the outlet no longer agree. Behind a parapet the outlet, hopper and downpipe run inside the building line, so a blockage puts water into the structure rather than down the wall. A coping and a cavity tray are formed, not sealed, and a skylight, a lantern, a Velux, a hatch, a soil pipe or a vent pipe each get a collar.

And the build up. A solid stone wall has to be able to dry, so this matters more here than on a modern house. PIR insulation above the deck with the vapour control layer under it keeps the dew point away from the joists and stops the condensation and interstitial damp that appear in a roof which has never leaked. A ventilated cold roof still suits a store. BS 6229 is the code of practice. A yard roof is a day, a back addition 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 back addition reached down a stone passage, a balcony over a bay on a seafront terrace and a flat roof over a shop yard in the town 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 Swanage, Herston, Durlston, Langton Matravers and the BH19 villages behind the town, 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.