Flat roofing in Thorney Hill

Extensions and garden rooms. The usual re-cover. EPDM rubber where the shape is a plain rectangle, laid as one sheet with bonded seams. GRP fibreglass where there are kerbs, a step in the level or a corner to work round, because it is laid wet and forms its upstands and edge trim in one piece. Single ply, welded at the laps, on anything with real area to it.

Garages, stores and outbuildings. Detached buildings weather from every side with nothing warming them, so felt built up in three layers with a mineral cap sheet over it goes hard and splits sooner here than the same covering tucked against a house. A modern torch on system on a dry deck is a solid answer on a big plain span. Whatever goes down, the boards decide it: plywood, OSB or chipboard on joists, and wet chipboard is finished.

Fixed down, not just laid down. On an exposed site the specification is as much about how the covering is held as what it is made of. A fully bonded membrane relies on the adhesive and on a sound deck under it. A mechanically fixed single ply relies on fixings at set centres, closer at the perimeter and corners than in the middle, because that is where uplift works hardest. Ballast is not an option on most light domestic decks. Getting this right is why an edge trim that has worked loose is a fault worth attending to rather than something cosmetic.

Falls, insulation and condensation. Firrings set the falls across the joists, and without them you get ponding and standing water sitting over every lap and seam. Tapered insulation corrects a fall from above. A warm roof takes PIR over the deck with a vapour control layer sealed underneath, holding the timber on the warm side of the dew point throughout. A cold roof holds the insulation between the joists and must be ventilated, or condensation and interstitial damp spoil the decking with no rain involved. BS 6229 is the reference for both.

Junctions, openings and rainwater. At an abutment the brick is chased out and a lead cover flashing dressed into it, not sealed with mastic, and a parapet has its coping and cavity tray checked. At the perimeter it is the edge trim, the drip and the apron. A rooflight, a lantern or a Velux sits on a formed kerb, and so does any soil pipe or vent pipe. Then the gutter, its hopper, the rainwater outlet and the downpipe. The everyday repairs are blisters, bubbles, a split or crack, and a lifted or failed seam.

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 on an open drive, an extension on a forest edge house and a stable or field shelter are three different jobs, whatever they add up to in square metres. 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 Thorney Hill, Bransgore, Burley Street and the BH23 addresses along the forest edge, with the New Forest National Park Authority as the planning authority. 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.