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 in Thorney Hill 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.

The area of a flat roof is the easy part. The deck, the falls and the edges decide the job.

What it covers. A detached garage on an open drive, an extension on a house backing onto the forest, and a stable or field shelter are different jobs. A garage often comes off a tower, anything taller wants a scaffold, and the work at height rules mean the platform is costed on its own.

The deck. Chipboard decks laid when these Thorney Hill houses were built are often soft by now where water has crept in at an edge. Sound ply is overlaid, soaked chipboard comes off and is replaced, and we check which you have before quoting.

Falls and trees. Leaves and needles from nearby trees block outlets, water ponds, and a membrane sitting in water fails early. Firrings to restore a fall and a proper outlet are priced one at a time, following the flat roof code of practice.

Wind at the edges. On an exposed site the edge trims and the perimeter take the uplift, so edges are bonded and fixed for it and single ply is fully adhered rather than loose laid.

Worth asking anyone else: will the deck be renewed or just overlaid, how will the fall be put right, and does the insulation reach Part L?

Thorney Hill is 6.8 miles from our Boscombe base. We re-cover flat roofs there and in Bransgore, Burley Street and the forest edge addresses of BH23. Any planning question goes to the National Park Authority, and notice of a renewed covering goes to the district council.

The company is Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719. Thomas Hannen, who owns it, lifts the corner of the deck and prices your flat roof in person. On Checkatrade, a verified customer scored the work 10 out of 10. The visit is on us, and so is the written quote with each line itemised. Before you book a visit in Thorney Hill, you can read our customers' Google reviews, word for word, on our reviews page.

Most repairs in Thorney Hill 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.