Flat Roof Repairs West Kirby

Flat Roofing in West Kirby

West Kirby has a great deal of bungalow in it. Across Grange and Newton and the roads climbing towards Caldy, the single-storey and dormer bungalow is the house type, and on a good many of them the back of the property has been opened out under one large flat roof: a kitchen, a dining room, sometimes a bedroom, all under a covering that can be the biggest single area of roof on the building.

That size is most of the story. A small garage roof is forgiving because the water has almost no distance to travel. A roof running the full width of the house has a long way to go from the high side to the gutter, a lot of joist between one support and the next, and a lot of covering out in the open that nobody looks at until something drips indoors. The failure modes are the same ones; they simply have more room to develop.

On a roof of that size the question worth asking is how few joints there are out in the open, and that is one of the reasons we replace in EPDM rubber. What the material is, how the deck beneath it should be specified and how the sheet is bonded down are covered on the EPDM rubber roofing page.

Bungalow Flat Roofs, Long Spans and Deflection

Deflection is the word for timber bending under load, and every joist does it. It is not a fault in itself, and the guidance expects it — that is precisely why BS 6229 says a flat roof should be designed to a fall of 1:40, so that after deflection, construction tolerance and a little settlement the finished roof still achieves the 1:80 minimum. On a short span there is room inside that allowance. On a long one there is a good deal less.

What it looks like once the allowance has gone is a dish. The middle of the roof sits lower than the edges, water that should be travelling to the gutter gathers at midspan instead, and the weight of it — water is heavy — presses the hollow a little further down. On an old felt covering the ponded area is usually where the surface breaks up first, because it is the part that never dries out and the part that freezes in winter.

Putting it right is not always a question of a new covering. Sometimes firrings can be cut and laid to build a working fall back across an existing structure. Sometimes the joists themselves are the problem, and anything involving new joists, altered spans or a wall that was taken out underneath is a structural engineer’s decision rather than a roofer’s. Before any of it, it is worth knowing what is actually under there: what is under your flat roof goes through it.

The Early Signs on a Large Single-Storey Roof in West Kirby

On a dormer bungalow you can usually see the whole of the flat roof from the dormer window, and that is the place to look from. What you are looking for is shape before surface: does the covering sit flat, or is there a shallow hollow where the light catches differently? A pond still sitting there two dry days after the rain stopped is telling you about the fall. Patches, old repairs and a surface gone dull and crazed are telling you about the covering.

Indoors the awkward part is that water does not come down where it got in. It runs along the top of a joist, sometimes several metres of it, and drops at the low point, so a stain in the back corner of a kitchen ceiling says very little about where the hole is. That is one reason a large bungalow roof is worth surveying properly rather than chasing one wet patch around with a tin of sealant.

Getting to the Roof in West Kirby

The good news on a bungalow is height. Most of the roof is at single-storey level, so the working platform is low and on many plots a tower will do where a two-storey job would want a full scaffold. The bad news is that a ladder still is not a platform. Where there is an open edge to work along there has to be something to stand on and something to stop a fall, and that is as true on a bungalow as it is anywhere else.

Volume is the other consideration. A roof this size means a lot of board going in, a lot of stripped covering coming out and a skip that has to stand somewhere — on the highway it needs a permit from Wirral Council. West Kirby plots are generally wide enough to get a full board through a side gate, although mature planting and a narrow path can make the carry longer than it looks on arrival. Scaffolding is quoted separately, once the ground has been seen.

Decks, Falls and Detailing in West Kirby

The deck under a large flat roof is a floor in all but name, and on a wide one how the boards are carried and where they are joined counts for more than the boards themselves. Firrings run with the fall, thick end to the high side, and they are cut and set out before a single board goes down, because a fall that is wrong on a big roof cannot be tuned out afterwards with the covering. What the boards themselves should be is a question about the material, and it is answered there.

Then the details take over. Where the flat meets the main pitched slope on a dormer bungalow, the covering is taken up the slope as an upstand and tucked under the tiles, and how far up it goes and how it is terminated there are not matters of taste. Where the roof drains, one gutter run or one outlet is taking everything a wide roof has collected, so its size, its position and whether anybody can reach it to clear it matter far more here than they would on a garage.