Durham Deep Retrofit | Wimbledon

Deep Retrofit & Low-Energy Extension of a Victorian End-of-Terrace Home

This project is a whole-house, deep retrofit of an early twentieth century end-of-terrace house in South London. The works stripped back the house to its shell of solid brick walls and re-lined the walls with insulation, airtight boards and new interior finishes to create a highly energy-efficient home. Energy performance was modelled using Passivhaus software which estimated a reduction in demand for space heating from 293 kWh/m2/yr to 77 kWh/m2/yr, a reduction of almost 75%. A photovoltaic array of 2.2 kWp was installed on the roof giving a predicted output of 1,795 kWh/yr or 15 kWh/m2/yr.

The home was also extended to the rear, replacing a cramped existing kitchen with a bright, open-plan kitchen and dining space. The dining area is defined by a vaulted pyramidal roof with exposed timber framing in white oiled ash. Fitted cabinetry throughout the ground floor brings character to the living areas and discreetly provides several facilities that were missing from the original Victorian layout: a bench to take on and off shoes, a walk-in cupboard for coats and a utility cupboard with a washing machine. Elsewhere, fitted cabinetry increases the amount of storage whilst maintaining generous spaces. Several new windows were added to the house to bring light into previously dim areas and an interior window between the hallway and living area helps to bring more space and light to they typically constrained entry. A frosted window in the kitchen runs down the back of the worktop illuminating the working area.

Location: South London, Wimbledon, Raynes Park

Property type: Victorian end-of-terrace

Scope: Whole-house deep retrofit and rear extension of an early 20th-century end-of-terrace home in South London, upgrading the building fabric, energy systems, and internal layout to create a low-energy, highly functional modern dwelling.

Key Features:

  • Deep whole-house retrofit & Passivhaus

  • Fabric-first upgrade

  • Renewable energy integration

  • Rear extension

  • Architectural timber feature

  • Integrated fitted joinery

  • Improved daylighting strategy

  • Spatial reconfiguration

Project Results:

  • ~75% reduction in heating demand (from 293 to 77 kWh/m²/yr)

  • 1,795 kWh/year renewable energy generated via 2.2 kWp solar PV

  • Significantly improved airtightness and thermal performance

  • Increased natural light

  • Expanded living space

  • Improved spatial efficiency

  • Enhanced comfort and usability

Photography: Agnese Sanvito  

Featured in: Don't Move Improve awards 2025