Chapter 1: Why does the ceiling below a valley in our West Byfleet house stain after every storm?
What we find
A valley is the trough where two roof slopes meet, and on a house with bays, dormers and a rear wing there can be several of them. On Edwardian roofs the valley is usually lined with sheet lead, laid on boards and tucked under the tiles on both sides. Lead lasts a long time, but it expands and contracts with every sunny day and cold night, and old sheets crack along the folds. Pine needles and leaf mould then pack into the channel and hold water against the cracks.
Indoors you will see a brown ring on the ceiling or the wall below the valley, often worse after a long wet spell than after a sudden downpour. Tiles on either side can look perfect from the lawn, which is why valleys get blamed on the wrong part of the roof for years.
What we fix
We start by clearing the debris and photographing the lead from end to end, because a split can be a short patch job or the sign that the whole sheet has gone. A local crack can be repaired with a lead patch welded or dressed into place. If the sheet is thin, buckled or holed in several places, we lift the tiles along the valley edge, replace the lining with new lead and relay the tiles on new battens so the overlap is right.
Typical UK prices reported for lead work on a chimney run from £350 to £920; a valley is priced on its length and access once we have measured it. Your fixed quote follows the survey. Details of the lead detailing are on the lead roofing and leadwork service page.