Notting Hill Villa: Lead Valleys and Basement Waterproofing, West London

Project Overview

The house is a detached villa of four storeys over a basement, built more than 120 years ago, with a central slate roof, lead valleys and parapet gutters, several chimney stacks, a top flat roof and a small lead terrace over the entrance. Water was coming into the top-floor rooms and had caused an electrical fault.

The owners came to us through another client. The roof was surveyed and priced first; a specialist damp survey of the lower ground floor followed, and the basement work was added as two written variations, agreed before work began. Progress went to the owners in a weekly written report with photographs.

Finding the Leak

The cause was the lead in the valleys: fatigued and split along the rolls, with failed upstands. The parapet lead was sound and was kept. Every valley was renewed in new code 7/8 lead, in correctly sized bays, welted and clipped on new building paper, and three courses of slate were lifted along each valley so the new lead could be dressed higher under them. Broken slates were replaced to match, the ridges repaired and the tiles cleaned, and the outlets, downpipes and hopper heads were enlarged so the roof clears heavy rain.

Scaffold went up on one elevation only, so no materials came through the house, and the top-floor rooms were sheeted and the route through protected. The damaged top-floor rooms were repaired and redecorated.

A Basement Store Made Dry

The store under the entrance steps took ground water at the junction of wall and floor in heavy rain, and its plaster was blown and salting. When it was opened up, the old render was more than 50mm thick and the brickwork behind it had gaps, so the walls were scabbled and repaired and the floor tiles and screed lifted.

A specialist who is a member of the Property Care Association then applied a 25mm waterproof render system to the four walls, a ledge and the ceiling, with movement joints, seals at every service entry and a flexible seal at the wall-floor junction, and slurry coats over the slab lapping up the walls. The render follows the curve of the historic front wall. After about three weeks of curing, the store was finished in vapour-permeable paint.

Reinstated to Match

Nothing was fixed through the new tanking. The store was given a new screed over the slurry, plaster kept clear of the floor, electrics surface-mounted and bonded, skirtings glued and the door refitted on battens. The floor tiles were matched like for like and laid and grouted to the original pattern. In the basement gym, the blocked drainage at the foot of the planted wall was cleared and repaired and the walls were replastered.

How the Job Ran

1. Survey: the roof inspected and priced, and a specialist damp survey of the lower ground floor, with a written proposal agreed before work began.
2. Roof: scaffold up on one elevation, every valley renewed in new lead, ridges repaired, terrace and top flat roof completed, outlets and downpipes enlarged.
3. Basement: store stripped, brickwork repaired and the waterproof render applied, then left to cure properly before any finishes.
4. Reinstatement and handover: store rebuilt inside, floor tiles matched and laid, top-floor rooms redecorated, and a joint inspection with the owners.

Scope of Works

Certificates and Handover

The works were completed in October 2026 and inspected jointly with the owners. The roof work carries Alstruct's 10-year workmanship warranty.

The Result

A dry top floor, a roof that sheds water the way it was designed to, and a basement store that is usable again, finished to match the rest of the house.

Read our guides: Leaking Lead Valleys and Gutters: Signs, Repair or Renewal and Basement and Cellar Damp: Tanking, Injected DPC or Membrane?.

If you are planning similar work in Notting Hill or nearby, see our Notting Hill page or browse our other projects.