Flat roofing in Freshwater and Totland

The wall first. On a solid masonry house the abutment does as much work as the covering. The upstand has to be turned up high enough and the cover flashing has to be lead, dressed into a chase raked out of a mortar joint and pointed back. Run the membrane up the wall and seal the top with mastic instead, and you have built a shelf that holds water against brick or stone that will absorb it. That is why so much of the damp in these houses shows on the wall beside a flat roof rather than on the ceiling under it.

Then the deck and the fall. A Victorian back addition often has plain boarding across the joists rather than plywood, OSB or chipboard, and it was rarely laid to any fall at all. Firrings over the joists, or tapered insulation as part of a warm roof, get water moving to the rainwater outlet. Ponding leaves grit and moss sitting on the surface and keeps the roof from drying, and standing water in one corner usually means the fall and the outlet disagree. A bubble underfoot is water already in the boards.

Then the covering. Where it is one failure we repair it: a split along a lap, a blister lifted clear of the deck, a seam that has let go. Felt is cut out, primed and welded under a fresh cap sheet. GRP fibreglass with a crack at a joint is ground back and re-laminated. EPDM rubber is cleaned and bonded down again. Where it has all hardened we strip and re-cover: rubber in a single sheet, fibreglass where there is a kerb or an outlet to form round, a built up three layer torch on felt system, or single ply on a wider area. An old lead roof behind a parapet that is still sound gets left alone, and we will say so.

Then the rest of the detail. A parapet, a coping and a cavity tray are formed rather than smeared over. The drip and apron at the front edge are made to throw water off the wall below. A skylight, a lantern, a Velux, a hatch, a soil pipe or a vent pipe each need a collar. And the gutter, hopper and downpipe get checked, because a blocked one backs water up under the trim and reads from inside as a failed roof.

And the build up. An old house has to be able to dry, so this matters more here than on a modern box. A warm roof puts PIR insulation above the deck with the vapour control layer below it, keeping the dew point away from the timbers and stopping the condensation and interstitial damp that appear in a roof which has never actually leaked. BS 6229 is the code of practice. A porch 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 porch roof over a front door, a flat topped bay on a Victorian terrace and a back addition hemmed in by a boundary wall are three different jobs before anything 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 Freshwater, Totland, Colwell, Norton and the PO40 side of the west Wight, and the 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.