Roofing and Leadwork London
Lead valleys and gutters, re-slating, flat roofs, chimneys and rainwater goods, for London period houses and new extensions.
A Roof That Sheds Water
At a glance: Alstruct carries out roofing and leadwork across London, on its own or as part of a renovation, extension or loft conversion: renewing lead valleys, parapet and box gutters, re-slating pitched roofs, building insulated flat roofs, repairing chimneys and ridges, and enlarging outlets and downpipes. At a Notting Hill villa we traced water in the top floor to split lead valleys and renewed every valley in code 7/8 lead.
Most roof leaks we are asked to look at on London period houses come from the lead: valleys, parapet gutters and flashings that have split with age, or outlets and hoppers too small for heavy rain. We inspect the roof first and find where the water is getting in, then give you a written proposal that says what will be repaired, what will be renewed and what is sound and can be kept. On the Notting Hill villa the parapet lead was sound and stayed, while every valley was renewed.
Where lead is renewed, it goes down in the right code and in correctly sized bays, welted and clipped on new building paper, with the slates beside it lifted so the new lead can be dressed up under them. Our guide to leaking lead valleys and gutters explains the signs to look for, when a patch is enough and when the lead needs renewing.
Because we are a main contractor, the work around the roof is covered too: the scaffold, protection of the rooms below, repairs and redecoration to ceilings that have been damaged, and the insulation and rooflights when a roof is stripped. On a loft conversion or extension the roof coverings, leadwork and flashings are built into the programme, and on a renovation the roof is often the first trade on site, so the house stays dry for everything that follows.
Every job is backed by the same accreditations and insurance: CHAS Elite, Constructionline Gold, Federation of Master Builders membership and £10 million public liability insurance, and the roof work on the Notting Hill villa carries our 10-year workmanship warranty.
What We Do
Lead valleys and gutters
Valleys, parapet and box gutters renewed in new lead in correctly sized bays, welted and clipped, or repaired where the lead is still sound. See leaking lead valleys.
Slate roofs and re-slating
Pitched roofs stripped and re-slated with new insulation, broken slates replaced to match, ridges repaired, and original slates reused where they are sound.
Flat roofs
Insulated warm deck flat roofs in GRP or a membrane system over extensions, outriggers and loft skirts, with rooflights and integrated gutters where the design needs them.
Lead dormers, flashings and terraces
Lead dormer cheeks, flashings at every roof junction, and repairs to small lead terraces and top flat roofs.
Chimneys
Chimney stacks repaired, stitched with steel rods and repointed, or given a new chimney support.
Gutters, outlets and downpipes
Larger outlets, hopper heads and downpipes so the roof clears heavy rain, and new gutters and downpipes as part of an extension or renovation.
Rooflights
Velux and fixed rooflights set into new and existing roofs, including a vaulted ceiling under a rooflight set so only one rafter had to be cut.
Roofs on extensions and lofts
The roof structure and coverings for a house extension or a slate mansard or dormer loft, matched to the existing roof.
Examples From Our Projects
- Notting Hill Villa, W11: water in the top floor traced to fatigued, split lead in the valleys. Every valley was renewed in code 7/8 lead with three courses of slate lifted along each one, the ridges repaired, the terrace and top flat roof completed, and the outlets, downpipes and hopper heads enlarged, all from a scaffold on one elevation. See the project.
- Leytonstone kitchen extension and re-roof, E11: the main roof stripped and re-slated with new insulation under a temporary roof on the scaffold, two Velux rooflights added, and the rear extension given a new insulated timber pitched roof built as a warm deck with integrated gutters. See the project.
- Hammersmith terrace rebuild and loft floor, W6: a rear mansard in slate to match the existing roof, insulated to a U-value of 0.13, with code 5 lead dormer cheeks, GRP warm deck roofs over the outrigger and loft skirt, and the chimney stitched and repointed. See the project.
- Bow Victorian terrace renovation, E3: a new flat roof over the rear extension, with leadwork, box gutters, hoppers and downpipes detailed around large-format structural roof glazing. See the project.
- Archway Victorian terrace, N19: slate roof works with the original slates removed and reused where possible and new slate laid, alongside a rebuilt loft and rooflights to the loft and extension. See the project.
Water coming through the ceiling?
Send us photos of the ceiling and the roof
Tell us when the stains appear and what you can see from outside, and we will arrange a roof inspection.
Send an enquiry Call 020 8080 8240CHAS Elite · Constructionline Gold · FMB member · £10M public liability
How we price
- A fixed price for the agreed scope. After a site visit we send an itemised quote, set out trade by trade and based on a complete specification, with no provisional sums for items we have not properly scoped.
- A JCT contract. The work runs under a JCT building contract, the Minor Works form on our published projects, with a defined programme.
- No change without a written price. If you change the scope, or the work turns out to need more than was agreed, we send a written variation with its cost first, and that work goes ahead only once you have agreed it.
- A 10-year workmanship warranty. It covers our workmanship and starts on the day the finished work is handed over to you.
The full wording is in our terms. For typical London figures, see our cost guides.
Frequently Asked Questions
Do you take on roof repairs on their own?
Yes. We carry out roofing and leadwork on its own, such as renewing lead valleys, repairing slates and ridges or enlarging outlets and downpipes, as well as roof work as part of a renovation, extension or loft conversion. At a Notting Hill villa the roof was the main job, with damp work in the basement added later as agreed variations.
How do you find where a roof is leaking?
We inspect the roof and look at where and when the water appears inside. Common causes on period houses are a split in the lead, a failed upstand where lead meets a wall, or a blocked outlet or hopper that lets water back up under the laps. The inspection usually shows which, and the proposal says what needs repairing and what is sound.
Can split lead be patched rather than renewed?
Small splits in otherwise sound lead can be repaired by welding lead patches. Tape, bitumen and flashband patches are short-lived because they cannot move with the lead. Where splitting is widespread, the bays are too long, or the slates beside the valley are being lifted anyway, renewing the lead in correctly sized bays is usually better value.
Do I need permission to repair or replace my roof?
Like-for-like repairs usually need neither planning permission nor a building regulations application, within the Planning Portal thresholds of 25% of the building envelope and 50% of the roof. Listed buildings, Article 4 directions and changes of material can need consent, and scaffold on the pavement needs a licence from the council. We check the position for your address.
How is roofing work priced?
Each job is priced after an inspection as a written, itemised quote. On a London house the scaffold is often a large part of the cost, so we plan the access carefully: at the Notting Hill villa one elevation was enough, and nothing was carried through the house. Our lead valleys guide gives published trade figures for small repairs.