Flat roofing in Christchurch

Balconies and terraces you walk on. Common here because so much of the housing is flats. A walked on deck takes punishment a garage roof never sees, so it wants a system made for it: a reinforced GRP fibreglass finish, or a single ply with a walkway, laid over insulation that will carry the load. The threshold is the critical bit. An upstand at a door has to be high enough or the water comes back over it, and where headroom is tight the answer is a drainage channel rather than a shortcut.

Parapet roofs behind an older frontage. Plenty of the town centre and the older terraces have a flat roof hidden behind a parapet wall, draining to one internal outlet. That is a design with no margin: block the outlet and the roof becomes a tank, and the first thing you see is a damp patch at the top of a wall. We clear and re-form the outlet, check the coping and the cavity tray, and dress a proper lead cover flashing into a chase rather than relying on mastic.

Extensions, garages and dormer tops. These come back in EPDM rubber where the shape is simple, GRP fibreglass where there are kerbs and detail, or torch on felt built up in three layers under a mineral cap sheet where a robust covering matters more than the finish. Single ply, welded at the laps, is for the larger areas.

What is underneath. Plywood, OSB or chipboard on joists, with firrings setting the falls. Chipboard that has been wet is finished. If the falls were never right you get ponding and standing water, and every seam and bonded lap under a puddle ages faster than the rest. Tapered insulation corrects a fall without raising the joists. On a warm roof the PIR sits above the deck over a taped vapour control layer, which keeps the timber warmer than the dew point. A cold roof needs a ventilated void or you get condensation and interstitial damp instead of a leak. BS 6229 sets out both.

Details and rainwater. Blisters, bubbles, splits and a crack at a kerb are the usual faults, along with a lifted or failed seam at an abutment. Round the edges it is the drip, the edge trim and the apron into the wall. Openings mean a rooflight, a lantern or a Velux on a kerb, and any soil pipe or vent pipe through the decking. Then the downpipe, the hopper, the gutter and the rainwater outlet itself. Close to the water, salt shortens the life of a fixing and an aluminium trim, so those are specified to suit.

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 balcony deck on a block of flats, a parapet roof behind a shopfront and a rear extension on a Victorian terrace are three different jobs, and the access separates them more than the area does. 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 Christchurch town, Purewell, Stanpit, Somerford and the BH23 addresses, with BCP Council as the authority for anything notifiable. 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.