Dormer and Bay Roof Repairs in Manchester

Why the small roofs go first

There is an order to it. A bay roof is a metre or so of lead or felt with an abutment along the back, a drip along the front edge and a return at each end. Four junctions and almost no surface, so the surface is rarely what failed. The back abutment usually goes first, because the flashing was never cut into the brickwork and somebody ran a bead of mastic along the top instead. Next is the front drip, where the covering was dressed too short and water creeps back under the edge rather than dropping clear of the wall. On dormers it is the cheeks, where the vertical face meets the pitched covering and the soakers were skipped. On a porch or a canopy it is the wall junction again, for the same reason.

How to read it yourself

Stand outside in heavy rain and watch the front edge of the bay roof. Water should drop clear of the wall, and water tracking back under the edge and down the brick is a drip dressed too short, which on a dry day shows as a darker band on the wall below. Inside, look at the wall directly under the back of the bay rather than at the ceiling. Damp there that dries out in a settled fortnight and returns after wind and rain is water off the roof, not water out of the ground. In the loft you can only check a dormer, and what you want is a wet rafter foot or a dark stain down the timber behind the cheek. Do not put a ladder against a bay or a canopy for a closer look, because none were built to be stood on.

What it does if it is left

These roofs sit directly over rooms people use, so the leak gets noticed early and then lived with for years. Outside, the pointing under the abutment washes out and the brickwork below stays green all year. Inside, the plaster blows in a patch roughly the width of the bay. Under the covering, the boarding and the bearers take it in at the back edge where the water sits longest, and once they are soft there is nothing left to fix a new flashing to. That is where a straightforward repair turns into taking the whole roof off the bay and rebuilding the deck.

Bays, dormers and porches on Manchester housing

The Victorian and Edwardian houses around Monton, Prestwich and Eccles carry small lead bay roofs with an apron dressed into the brickwork, and a lot of that lead is code 3, run in one long length with nowhere to go. Lead moves every day the sun is on it, and lead that cannot move splits along the fold instead. The interwar semis bring a different set: a tiled or felted canopy over the front door, and bay roofs finished in whatever was cheapest that year. Then the dormers, both the original ones and the ones that came with a loft conversion, and on the converted ones the cheeks and the flat top are the newest part of the roof and the worst detailed.

How we do it properly

The rule on a small roof is that the detail has to shed water on its own, with no help from a sealant. A back abutment gets a flashing cut into a raked joint and wedged, not stuck on the face of the brick. Lead goes in at a code heavy enough for what that piece is doing, and it goes in in bays with a welt or a drip between them so it has room to move with the weather. The front edge gets a drip formed to throw water clear of the wall. Cheeks get soakers dressed under the covering rather than a strip of flashing over the top of it. Where the surface itself has gone we recover the flat area in lead, felt or a membrane, and Dave tells you which he thinks yours wants and why, in a free written quote, before anything is ordered.

Repair or replace, and what affects the price

Most of these are repairs: a back flashing renewed properly, a drip reformed, soakers put in where there never were any. Replacement is the honest answer when the deck has gone soft, when the lead has split in several places rather than one, or when the detail has been sealed over two or three times and there is nothing clean left to dress to. What moves the figure on a bay or a dormer is not area, because there is barely any. It is the number of returns and corners, since every corner is a detail formed by hand on the day. Then whether the covering is lead or felt, whether the boarding underneath has to come off, and what the wall is made of, because chasing a flashing into soft Victorian brick is a different afternoon from cutting into stone. Access counts too, since a front bay over a garden wall or a pavement may want a tower rather than a ladder. All of it goes in the free written quote, itemised, with no obligation to go ahead. One thing we will not do is chase a leak on a bay or a dormer with sealant. If the detail cannot shed water on its own, we take it off and form it again.

Frequently Asked Questions

There is damp on the wall inside my bay. Is that the bay roof?

Often, and it is worth ruling out before anybody sells you a damp proof course. Water getting in at the back of a bay roof runs down inside the wall and shows on the plaster below, which looks very like damp coming up out of the ground. The tell is the tide mark: ours starts high and works down.

Is it always the roof?

No, and we would rather say that early than at the end. On a bay the water can just as easily be coming in at the window head, through the sill, or through open pointing above the roof. If that is what we find, we will tell you plainly, and none of it is work for us to do.

Someone has already sealed mine and it still leaks.

That is the usual history on these. Mastic over a failed junction holds for a season or two, then traps water behind it and leaves the timber worse than it found it. We take the detail back to something that sheds water rather than something that relies on a seal.

My dormer has tile hung cheeks and they look perfect. Can it still be the dormer?

Yes. Tile hanging is a rain screen, not a waterproof layer. What actually keeps the water out is the soakers and the flashing behind it, and those can have failed completely while the tiles look fine from the pavement.

Can you repair just the bay and leave the rest of the roof alone?

Yes. A bay, a porch or a canopy is a self contained roof and we are happy to do one on its own. If we can see something else worth knowing about while we are up there we will tell you, but it does not go in the free written quote unless you ask for it. And felt is not automatically wrong on one of these: laid to a decent fall with a formed drip it runs for years, so we would sooner relay felt properly than talk you into lead you do not need.