Flat roofing in Bere Regis

How they fail. Felt goes brittle and splits along a crease or a lap. Blisters form where damp has been shut in under the covering. A failed seam at an upstand lets water behind the whole roof rather than through one hole. And ponding, water standing in the same corner weeks after the rain, is usually a blocked outlet or a fall that was never there.

What goes back on. EPDM rubber for a plain rectangle, laid in a single sheet so there is no lap to argue with later. GRP fibreglass where there is shape to work round, because the upstands and kerbs are laminated in one with the deck. Torch on felt where a three layer built up system with a mineral cap sheet suits the building better. Single ply, hot air welded rather than bonded, on the bigger areas.

The deck decides the job. Old decking is plywood, OSB or chipboard, and chipboard that has been wet for a season is finished. Underneath it the joists carry firrings, and the firrings are what create the fall to the rainwater outlet. A roof laid without one holds standing water for ever. Where re-firring is not practical we build the fall in tapered insulation. BS 6229 is the code the falls are set out from.

Where the insulation sits. Put it above the deck, over a vapour control layer and under the covering, and every bit of timber stays warm and dry. That is a warm roof, and PIR is what we use for it. Push the same insulation down between the joists and you have a cold roof, with the deck sitting on the wrong side of the dew point. Moist air from the room finds it, interstitial condensation forms where nobody can look, and the boards go soft from the top down. Part L asks for the upgrade whenever a covering over a heated room is renewed, and building control check it.

The fiddly bits. Where the roof dies into a wall, the flashing has to be cut in rather than stuck on. We rake out a chase, dress lead into it as a cover flashing, and on a cavity wall set a tray above so nothing runs down the inner leaf. A parapet gets its coping bedded and an apron under it. Anything coming through the roof stands on a kerb of its own: a rooflight, a lantern, a Velux style flat roof window, a hatch, a soil and vent pipe. The open sides turn over a drip trim, and the rainwater outlet feeds a hopper, a downpipe or the gutter. A garage is a day, a bigger extension two or three working days, and we say how long up front.

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 cottage with a flat roofed back addition, a detached garage at the end of a drive and a modern extension off a kitchen are three different jobs before anyone unloads. 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.

There are a lot of listed entries around Bere Regis, and they are mostly the old cottages and farm buildings rather than the newer housing. If your house is one of them, the listing covers the whole building. That includes a flat roof over a back addition that nobody can see from the road, and it includes what the covering is made of.

In practice that means a change from felt to fibreglass or rubber is a change of material and wants consent before it happens, not after. It is free to apply for and it takes time, so it is worth starting the moment you know the roof is going. Where the original was lead, a lead flat usually goes back and the conversation is short. We will quote both ways and put the consent position in writing with the price, so nobody is guessing. If your house is not listed, none of this touches you and the covering is your choice.

We cover Bere Regis, Briantspuddle, Winterborne Kingston, Wool and the rest of BH20. 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.