This job in Frodsham was on the flat top of a bay window, the narrow roof that sits between the window head and the bottom row of tiles on the main roof. Jobs like this are often filed under leadwork, because bay tops and their junctions with the house were traditionally covered or flashed in lead. On this one, the photos show a different approach: a new deck and a single sheet of black rubber membrane.
The four photos follow it through, from the bare boards to the finished corner trim.
Stripped back to the boards
The first stage shows the old covering gone and a fresh sheet of timber decking fixed across the bay. Behind it, where the bay meets the wall of the house, the bottom course of concrete tiles has been lifted enough to expose the batten and the green underlay, so the new covering can run up under the tiles rather than stopping short against them.
That junction is the part that matters most. Water running off the main roof lands right on it, and if the covering is simply butted up to the tiles, rain gets behind it. Carrying the membrane up and under the tile course means water is shed on top of the new roof rather than behind it.
Rubber membrane and edge trims
In the later photos the deck is covered with one piece of black rubber membrane, turned up at the back and finished at the front and ends with black edge trims. In one, a cordless drill, a knife and a mug of tea sit on the membrane while the upstand against the tiles is still being worked in.
The finished shot shows the corner of the bay, where the trims meet in a neat moulded corner piece above the window frame, with the black gutter running along beside it and the tiles sitting back down over the green underlay. For more on how these membranes are laid, see our flat roof and rubber roofing page.
- New timber deck boards over the bay
- Black rubber membrane in a single sheet
- Junction with the tiles opened up so the new covering could be lapped in
- Black edge trims with moulded corner pieces
Questions About This Kind of Job
Is lead the only option for a bay window roof?
No. Lead has long been used on bays and still works well, but a rubber membrane with edge trims is another sound way to cover a small flat bay top, and it has no scrap value to attract thieves.
Why does my bay window leak where it meets the house?
Usually because the junction between the bay covering and the main roof or wall has failed, so water running off the tiles gets behind the covering. That junction needs to be lapped properly, not just sealed.
Can you repair a bay roof without scaffolding?
Most single-storey bay tops can be reached from ladders or a small platform. It depends on the height and the ground below, which we check when we visit.
Do you cover Frodsham?
Yes. See our roof repairs in Frodsham page, or get in touch to arrange a visit. Bay roofs are part of our everyday roof repairs work.
