Hammersmith Terrace: Rebuild, Loft Floor and Full Refit, West London
A Hammersmith terrace reworked from the lower ground floor to a new loft floor: a new steel frame and footings, a slate mansard and lead dormers in the roof, waterproofed lower ground rooms, a full rewire and new heating, and a finish in oak, Yorkstone and birch ply. Completed in April 2026.
Project Overview
The house is a three-storey mid-terrace over a lower ground floor, built more than a century ago in solid brick. The owners wanted a family house that worked from the bottom to the top: a kitchen, pantry, utility, guest bedroom and shower room at lower ground level, and two new bedrooms with a family bathroom in the roof.
The job ran under the RIBA Domestic Building Contract 2018. An independent contract administrator inspected and certified the work every fortnight, seventeen certificates in all, and the structural design, party wall process and planning sat with the owners' own professional team. The owners moved back into the finished house in April 2026.
A New Structure Underneath
At lower ground and ground floor level the existing structure was taken out and replaced to the engineer's design: new footings, and a new steel frame of 254 and 203 universal columns and beams in S355 steel, bolted at the joints and protected with fireboard or intumescent paint. Where welding was done on site it was certified for building control, and the engineer confirmed the chimney support plates and the protection of a drain that runs through the new ground beam.
The chimney was stitched with steel rods and repointed, and the uneven lower ground floor levels were brought true with self-levelling screed, with the stair adapted to suit.
Damp Dealt With Before the Finishes
Two damp problems came to light once the lower ground floor was opened up. Where chimney breasts had been removed in the past, the old damp-proof course had failed; it was replaced with injected cream and a four-coat waterproof render. The store under the front steps was far wetter, from ground water, rain coming through the steps above and condensation, so it was tanked with a cementitious waterproofing system to the floor and walls, and the steps were rebuilt and waterproofed from above.
The waterproofing carries a 10-year structural waterproofing guarantee, running to December 2035.
A New Floor in the Roof
The loft became two bedrooms, a family bathroom and eaves storage. The rear is a mansard in slate to match the existing roof, insulated to a U-value of 0.13, and the dormer cheeks are code 5 lead on a breather membrane over marine ply, lined with insulated plasterboard. The lower roofs over the outrigger are a lead-grey GRP warm deck on 180mm of insulation, and the party wall was built up in London stock brick.
How the Job Ran
- Strip-out: scaffold with a temporary roof, then strip-out and demolition at lower ground and ground floor.
- Structure and roof: footings, the new steel frame, the loft structure and the roof coverings, with drainage renewed below ground.
- Plastering and tiling, with the job running ahead of programme.
- Glazing: the owners' steel-framed garden doors, windows and fixed rooflight installed.
- Finishes: kitchen, joinery and decoration, with final walk-rounds alongside the contract administrator.
- Handover: boiler and electrics certified, the owners back in, and practical completion certified.
Scope of Works
Structure
- Demolition and rebuild at lower ground and ground floor on new footings
- New steel frame (254x254 and 203x203 universal columns and beams, S355) with fire protection
- Chimney stitched with rods and repointed
- Self-levelling screed to the lower ground floor and an adapted stair
Roof and loft
- Slate mansard and lead dormers with sash windows
- GRP warm deck roofs to the loft skirt and outrigger
- Three Velux rooflights
- Two loft bedrooms, a family bathroom and eaves storage
Damp and waterproofing
- Injected damp-proof course and four-coat waterproof render
- Cementitious tanking to the store under the front steps, with the steps rebuilt and waterproofed
Services
- Full rewire, certified for the whole property
- Vaillant ecoTEC 35kW boiler, unvented cylinder and column radiators
- Low-profile underfloor heating to the lower ground kitchen, bedroom and bathroom, and to the loft bathroom
- Ducted air conditioning to three bedrooms
- Mains-linked heat, smoke and carbon monoxide alarms and FD30 fire doors
Finishes
- Quarter-sawn oak engineered flooring
- Bullnosed Yorkstone front and basement steps
- Encaustic, herringbone and terracotta tiling
- Birch-ply and MDF joinery, cornices and a ceiling rose
- Twelve new internal doors and a new ground floor WC
Certificates and Handover
The electrical installation certificate for a new installation covering the whole house was signed on 7 April 2026, and the gas work was certified under Gas Safe the day before. The contract administrator certified practical completion on 22 April 2026.
The Result
A house that is new where it matters, inside a century-old shell: a sound structure and dry rooms at lower ground level, a full floor of bedrooms in the roof, and modern heating, electrics and fire safety throughout. The owners have since recommended us to their neighbours.
Read our guide: Basement and Cellar Damp: Tanking, Injected DPC or Membrane?.
If you are planning similar work in Hammersmith or nearby, see our Hammersmith page or browse our other projects.
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