Wimbledon Victorian Terrace: Extension, Loft and Low-Carbon Refit, South West London
A Victorian terrace in Wimbledon reconfigured, extended and taken off gas: a side infill extension around a new courtyard, a dormer loft bedroom and bathroom, an air source heat pump with underfloor heating and heat-recovery ventilation, breathable lime and wood-fibre insulation, and new gardens front and back. Completed on programme in July 2026.
Project Overview
The house is a three-bedroom Victorian mid-terrace in solid stock brick. The architect's scheme reconfigured and extended it: a ground floor side infill extension around an enclosed courtyard for the kitchen, a new first floor bathroom, and a dormer loft conversion with a double bedroom and family bathroom.
The job ran under the RIBA Domestic Building Contract 2018, with a party wall award agreed with the adjoining owner before the start. The owners moved back in on 3 July 2026, on programme.
Opening Up the Structure
The existing kitchen slab was broken out and the ground floor joists were replaced throughout. A new staircase in birch ply was built from the ground to the first floor, three chimneys were repaired with a new chimney support, and new rafters went in over the third bedroom. When the cement render came off the front, about 60 crumbling bricks were found and rebuilt in yellow stock brick.
A Breathable, Low-Carbon House
The house was taken off gas. An air source heat pump now feeds wet underfloor heating on the ground floor and radiators upstairs, with electric underfloor heating in the bathrooms, and a Brookvent mechanical ventilation with heat recovery system keeps the air fresh. The heat pump was commissioned at the end of the job, once every emitter was in.
The solid walls were treated as solid walls: wood-fibre insulation with lime plaster on the front wall, applied only once the masonry was below 15% moisture, aerogel plasterboard on the party wall, lime render outside in the courtyard, and breathable clay paint inside.
Finished in Natural Materials
The finishes are engineered oak, clay and quarry tiles, rubber bathroom floors and jute carpets, a birch-ply cut-string stair and joinery package, a bespoke stainless steel worktop, woodgrain sash windows to the front, a hardwood front door and new rear glazing. Outside, ten gabion cages form a retaining wall with a step, the rear is laid with about 20 square metres of grass-reinforced permeable paving, and the front has a new picket fence, with the excavated soil reused on site.
How the Job Ran
- Strip-out: start on site, strip-out and the kitchen slab broken out, with the loft frame following.
- Structure: chimney works, new ground floor joists, extension structure and roof.
- Shell and first fix: plastering, courtyard brickwork and first fix complete, rear glazing installed.
- Finishes: rear garden, decoration, front windows, kitchen and heat pump commissioning.
- Handover: the owners moved back in, on programme.
Scope of Works
Structure
- Kitchen slab broken out and ground floor joists replaced
- Side infill extension around an enclosed courtyard
- Dormer loft conversion with a double bedroom and bathroom
- Three chimneys repaired with a new chimney support, new rafters over bedroom three
- About 60 front-elevation bricks rebuilt in yellow stock
Energy and services
- Air source heat pump, wet underfloor heating downstairs, electric underfloor heating in bathrooms
- Brookvent mechanical ventilation with heat recovery
- Full rewire with a new consumer unit, surge protection and mains smoke alarms
- Wood-fibre insulation and lime plaster to the front wall, aerogel plasterboard to the party wall
Finishes
- Birch-ply cut-string stair and joinery package
- Kitchen with a bespoke stainless steel worktop
- Engineered oak, clay and quarry tiles, rubber and jute floors
- Three bathrooms
- Woodgrain sash windows to the front, hardwood front door, new rear glazing
Outside
- Ten gabion cages forming a retaining wall and step
- About 20 square metres of grass-reinforced permeable paving on a Type 1 sub-base
- Front picket fence, lime render to the courtyard, making good to both neighbours
Certificates and Handover
The house was handed back on programme, 32 weeks after the start. The full rewire is covered by an electrical installation certificate, and we signed the building regulations declaration as principal contractor.
The Result
A Victorian terrace that keeps its character and runs like a new low-carbon house: no gas, heat from the air, fresh air without draughts, and walls that are allowed to breathe.
Read our guide: A Heat Pump in a Victorian Terrace: What It Takes.
If you are planning similar work in Wimbledon or nearby, see our Wimbledon page or browse our other projects.
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