Cadogan Terrace: A Low-Carbon Retrofit of a Victorian Home

Project Overview

Construction is commencing on Cadogan Terrace, a deep retrofit and partial extension of a mid-19th-century Victorian end-of-terrace house in East London. Led by Arboreal Architecture, the project combines conservation-led design with a fabric-first approach to energy performance, material reuse and the reduction of whole-life carbon emissions.

Originally built around 1850, the three-storey house, including a basement, has undergone several phases of alteration throughout its history, including a period of non-residential use as a post office. The building retains much of its original character, alongside later additions that reflect its changing function over time.

The existing structure comprises solid load-bearing brickwork in Flemish bond, timber-framed floors and a distinctive butterfly roof currently finished in fibre-cement slates. Internally, solid masonry walls, timber stud partitions and brick-infill construction form a layered structural arrangement. A later ground-floor extension accommodates the kitchen and bathroom, while the existing windows are single-glazed timber sashes.

The site occupies a narrow east–west-oriented urban plot, with the frontage overlooking Victoria Park and mature trees providing a green outlook to the rear. These conditions inform the design approach, particularly the opportunity to improve daylight penetration and strengthen the relationship between the interior and the surrounding landscape.

A Conservation-Led Approach to Retrofit

The project retains the legibility of the existing Victorian building while selectively reconfiguring its internal layout to improve spatial quality, daylight distribution and connections between the front and rear of the house.

Rather than undertaking a wholesale reorganisation, the design focuses on targeted interventions that respond to the building's existing structure and spatial characteristics. Adjustments to the rear extension and roof geometry are intended to bring more natural light into the ground floor, addressing the challenges of a narrow urban footprint.

New architectural elements will be clearly distinguished from the historic fabric. This approach allows the different phases of the building's development to remain legible, creating a dialogue between old and new without resorting to imitation.

Material reuse is integral to the design strategy. Existing components will be retained or reclaimed wherever technically and practically feasible, reducing demand for new resources and helping to limit the project's embodied carbon.

Reducing Embodied Carbon

The retrofit adopts a carbon-first approach, recognising that the environmental impact of a building extends beyond its energy consumption in use. Retaining the existing structure avoids much of the carbon associated with demolition, waste processing and the manufacture of replacement materials.

Where new materials are required, the specification prioritises low-carbon and bio-based options, including timber, wood fibre insulation, cork and hemp. These materials can offer lower embodied carbon than conventional alternatives, depending on their sourcing, processing, transport and end-of-life treatment.

Local sourcing and the reuse of existing materials will be considered alongside manufacturer supply-chain impacts. The project aims to align its embodied carbon performance with the RIBA 2030 Climate Challenge benchmark of less than 300 kgCO₂e/m², with the additional ambition of exploring whether biogenic carbon storage can bring the overall material balance towards net-negative embodied carbon.

A Fabric-First Energy Strategy

Improving the thermal performance of the existing building is central to reducing operational energy demand. The proposed works focus on enhanced insulation, improved airtightness and the careful treatment of thermal bridges, while responding to the constraints of the existing structure and its architectural character.

The project targets operational energy use below 35 kWh/m²/year, in line with the performance ambition set out in the RIBA 2030 Climate Challenge. This is a design target rather than a verified outcome, with final performance dependent on construction quality, commissioning and how the building is operated.

The house will be fully electrified, reducing reliance on fossil fuels for building services. A photovoltaic array is proposed within the south-facing butterfly roof, making use of the existing roof form to generate renewable electricity on site and reduce demand from the grid.

Healthy Interiors, Water Efficiency and Biodiversity

Environmental performance extends beyond energy and carbon. Internal finishes will prioritise low-emission, non-toxic materials to support good indoor air quality and a healthy living environment.

Water efficiency measures aim to reduce consumption to below 75 litres per person per day through the specification of low-flow fittings. Rainwater harvesting from the roof is also proposed for garden irrigation, with storage potentially integrated into the rear terrace.

Despite the constraints of an urban site, the landscape strategy will introduce native and pollinator-supporting planting. Opportunities to incorporate bird-nesting provisions, insect habitats and bat roost features into the building fabric will be explored where appropriate and compatible with the construction and conservation requirements.

Building on What Already Exists

Victorian house like Cadogan Terrace can be adapted to contemporary standards of comfort and environmental performance without losing sight of the value of its existing fabric. By combining selective spatial intervention, material reuse, low-carbon construction and a fabric-first energy strategy, the project seeks to reduce environmental impact while creating a healthier, more adaptable home.

As construction begins, the focus turns to translating these design principles into the building itself: retaining what can be retained, using resources carefully and improving performance through a considered relationship between architecture, materials and building services.

Location: East London, London Borough of Tower Hamlets

Property type: Victorian end-of-terrace

Scope: Deep retrofit and partial extension of a mid-19th century Victorian end-of-terrace house in East London, focusing on fabric performance upgrades, spatial reconfiguration, and low-carbon systems integration to transform the building into a high-efficiency, climate-responsive home.

Key Features

• Deep retrofit

• Significant energy reduction

• Retention and reuse of existing building fabric

• Selective spatial reconfiguration

• Butterfly roof with PV integration

• Low-carbon material strategy

• Improved daylighting strategy

• High-performance building envelope targeting RIBA 2030 energy standards

• Heritage-sensitive design approach