Roofers in Birdham

1.1 What a gust looks for

Wind finds the weakest edge first. On a pitched roof that is usually a tile at the verge (the edge where the roof ends at a gable), a ridge tile whose bedding has crumbled, or a slipped course at the eaves. Marley points out that on pitches under 30 degrees the slope facing the wind may be pulled hard by negative pressure, and a low-pitched roof on open ground is where we slow down and test every fixing by hand. Wienerberger says no single-lap tile should go on without a nail or clip of its own, whatever else is holding it in place. At the verge the end tiles are the first to lift, so we check that each is fixed down and that the pointing beneath it is sound.

1.2 Making a ridge hold

Since the 2014 revision of BS 5534, a ridge or hip tile is no longer left to its mortar bed alone; a screw, clip or strap holds it as well. We re-bed sound ridge tiles over fresh fixings, or fit a dry-fix system tested to BS 8612:2018, whichever suits the roof in front of us. After a gale, run your eye along the ridge from the road and the garden for a tile that has shifted, and look in the loft for daylight at the apex. Both checks cost nothing and catch trouble before a leak starts. Our ridge tile repairs page explains the options, and the roof repairs hub shows how we trace a leak to its source.

3.1 Choosing the covering

Three coverings dominate: felt, EPDM, which is a synthetic rubber sheet, and GRP, a glass-reinforced plastic skin laid in resin. Published lifespans are typical ranges, never promises. Less puts torch-on felt at 10 to 20 years and GRP at 25 to 40, while GreenSpec gives EPDM 20 to 30 years, and a poor installation fails far sooner than any of those. On a large roof an EPDM sheet means fewer joints, while GRP suits awkward shapes with upstands and corners.

3.2 When Part L comes into it

Approved Document L lists a new waterproof layer on a flat roof among the works that renovate a thermal element, which here means the roof itself. The test is extent. Renovate more than 50 per cent of that element, or more than 25 per cent of the building envelope in a major renovation, and the whole element must be upgraded; a new or replacement roof element is held to a limiting U-value of 0.15 W/(m²·K). That means insulation goes in with the new covering, and the build-up gets thicker. Ask any firm how the insulation will be laid and where the upstands will finish.

3.3 What the survey settles

Before pricing a flat roof we measure the area, probe for wet insulation, check the outlets and look at how water leaves the edge. Where branches overhang an extension roof, we also look for leaf build-up, which blocks outlets and keeps a roof wet long after the rain has stopped. Sunlight, standing water and debris all wear a membrane, and the survey records which of them is at work on your roof. Photographs of the deck, the edges and the outlets go with the written quote once the survey is done. Our flat roofing page covers the choices in more depth.