Flat Roofing in Corfe Mullen

First to go are the trims. An edge trim is a length of metal or plastic with a drip formed into it, holding the perimeter of the covering down and throwing water clear of the fascia. Fixings work loose, the joint between two lengths opens up, and water starts running back underneath instead of falling off the end. Replacing them is half a day and it saves the roof.

Next is the junction with the house. Wherever a flat roof meets a wall, the covering has to turn up as an upstand and something has to cap it. On the newer Corfe Mullen estates that is a cover flashing cut into a chase; on anything older it is lead worked over an apron. Mortar shrinks out of a chase, lead splits along a fold, and a parapet loses the bedding under its coping or never had a cavity tray behind it to start with. All of that is edge work and none of it means a new roof.

Then the outlet. It is the lowest point on the roof and everything ends up there, so it silts, and once it silts the roof holds water. Standing water is the accelerator: it works into a lap, lifts the seam and gets in underneath. We clear the outlet, the hopper, the gutter and the downpipe as a matter of course, and where a roof has always ponded we take the boarding up and re-cut the fall with firrings or tapered insulation so it drains where it was meant to.

The covering itself usually goes last, and it announces itself first. The mineral finish wears bald, blisters and bubbles lift, and the surface cracks wherever a thumb presses. One split is a repair: back to sound material, a new piece welded or bonded across it, the edge dressed flat. A dozen splits is a re-cover. What goes down then is EPDM as one cold bonded rubber sheet, GRP brushed on wet over new plywood and cured as a single fibreglass skin, three layer built up felt under a torched mineral cap sheet where the roof gets walked, or welded single ply across a wide span. Rooflights and lanterns come off and go back on kerbs we build up so the skylight sits above any standing water, and Velux units, loft hatches, soil pipes and vent pipes each take a collar.

And underneath everything, the deck. Chipboard was standard on this era of extension in Corfe Mullen and it does not survive damp, so once it goes soft at a corner it comes out and OSB goes down instead. The joists get looked at while the boards are up. If most of the covering is coming off anyway then the insulation standard is engaged, and the sensible build is warm: PIR above the deck with the vapour control layer under it, keeping the dew point out of the timber, rather than a cold roof depending on a ventilation gap nobody is ever going to inspect again. BS 6229 sets out the construction and regulation 23 of the Building Regulations is what brings insulation into it when a covering is renewed.

We do not price a Corfe Mullen flat roof by the square metre. The new covering is the easy part; the deck and the falls decide the price.

Which system. Built-up felt was the norm when these garages and extensions went on. Modern torch-on felt, a single-ply EPDM rubber membrane and GRP fibreglass each price differently, and each suits some roofs better than others. We tell you which we would lay and why, and how many layers.

The deck. Chipboard decks of that era swell when they get wet and never recover. If it gives underfoot it comes off, and we lift a corner before quoting to find out.

Warm roof or cold. A roof over a heated room is usually rebuilt as a warm deck, with insulation above the deck and the membrane on top, which raises the roof level. That changes the upstands, edge trims and flashings, and all of it is priced.

Falls and outlets. A roof with no fall ponds. Firrings put the fall back towards an outlet, and that outlet needs a downpipe that takes the water somewhere sensible on this clay.

Access. A garage at the end of a drive comes off a tower; a two storey rear extension needs scaffolding, which the work at height rules make a priced item.

Ask a rival firm to name the system and the number of layers, to say whether the deck is coming off, and to confirm that a warm roof, its insulation, the scaffold and the skip are included.

We price flat roofs across Corfe Mullen and on to Broadstone, Merley, Upton and Lytchett Matravers, in BH21 and BH16, eight and a half miles or so from our Bournemouth base in Boscombe. Dorset Council is the council for the village.

You deal with Thomas Hannen, who owns the firm and prices the roof himself when he comes out. Bournemouth Roofing & Building Ltd is registered in England and Wales; its company number, 15471719, is on the public register. On Checkatrade a verified customer rated us 10 out of 10. We charge nothing to visit or to send the written quote, itemised line by line. Before you book a visit in Corfe Mullen, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Corfe Mullen need no application at all. What decides whether a change to the outside of your house does is who the council is, whether a conservation area or a listing applies, and whether the place sits in a protected landscape.