Roofing in Alderholt

Concrete tile, and what forty years does to it. Most roofs in Alderholt are concrete interlocking tile, because that is what went on when the village grew and a third of the stock dates from 1983 onwards. What goes first is the sand faced surface, which weathers off and leaves an open textured tile that holds water and grows moss, then the mortar bedding at ridge, hip and verge, then the nails. Which of the three has failed is the difference between a day's work and a new roof.

Ridge, hip and verge. The commonest job on this stock. The old bedding comes off and the edges convert to a dry fix system: a dry ridge screwed onto a ventilated roll and a dry verge clipped along the gable. That is the mechanical fixing BS 5534 expects, it removes the detail that cracks and washes out first, and it ventilates the roof space at the same time.

Close to a quarter of the dwellings here are bungalows and many sit at a low pitch, which decides the covering before anything else does. Down at the shallow end you are into an interlocking tile or a sheet system, and a plain tile or a small slate will not weather at that angle whatever the brochure says.

Repairs are slipped, cracked and missing tiles, storm damage, and a leak traced back to where water genuinely enters rather than patched where the stain shows. When the nails snap, the batten ends are soft and the underlay tears in your hand, the covering comes off, rotten rafter feet are cut out, and it goes back on breathable membrane and treated battens with a matched tile.

Garages, porches and rear extensions go in felt, GRP fibreglass or EPDM rubber, with the deck looked at before the falls, upstands and outlet are priced, and chimney flashings, soakers, valleys and abutments in code rated lead cut short enough to move without splitting. Where the downpipe puts its water matters here, because the ground is cohesive and moves with the seasons, so a soakaway has to sit well clear of the building and Approved Document H says where roof water may go.

With the covering off, insulation, eaves ventilation and any condensation problem cost a fraction to sort while the access is already paid for, and Approved Document L sets the standard a renovated roof is expected to reach.

No rate per square metre: the area is the easiest thing to measure and the least useful thing to know. Plots are generous and most houses have a drive and a side gate, so scaffold and skip stand on your own ground, not the highway. How long the platform stands matters as much as its size, and the work at height rules are why it is a priced line rather than an extra.

Chimneys, valleys and abutments are priced one at a time. Ask whether the scaffold is in the price, whether battens and membrane are renewed or covered over, and who pays for the skip.

That is unusual on our patch and it takes a whole set of arguments off the table. A repair, a like for like re-cover, new rainwater goods and rooflights all sit inside ordinary householder permitted development, within the limits the Planning Portal guidance sets out: nothing more than 150mm above the existing roof plane and nothing above the highest part of the roof. No application, no consent, and no officer with a view on your tile.

So the decision comes back to the roof itself, and the questions are weight and pitch. Going from a concrete tile to a natural slate takes load off the rafters and is rarely a problem. Going the other way, or putting a heavy tile on a roof built for something light, means the timbers get measured before anything is ordered.