Sustainable House Extension in Regent’s Canal Conservation Area

Site Preparation and Heritage Conservation
As part of the conservation approach, we carefully dismantled the existing outbuilding while preserving historic Yorkstone pavers and safeguarding established vegetation, including a mature cherry tree. Our team conducted a provisional asbestos survey and safe removal, ensuring the site was cleared safely before beginning the extension work.

Sustainable Substructure and Foundations
The extension’s foundation utilizes screw-pile foundations, chosen for their minimal environmental impact. This stable base supports the Douglas Fir timber frame, which was sustainably sourced and selected for its durability and aesthetic appeal. We installed a Visqueen Radon R400 co-polymer membrane to protect against moisture and improve longevity.
Timber Frame and Lightweight Superstructure
A defining feature of this extension is the Douglas Fir timber frame, carefully constructed to minimize environmental impact while adding resilience and beauty. Each timber element was finished with Osmo UV Protection Oil, ensuring a natural look that aligns with the garden’s aesthetic. All timber meets Structural Grade 1-B under BS EN 975-1 standards, offering high strength and durability.

Green Roof System for Enhanced Biodiversity
The extension’s green roof features the Bauder Total Green Roof system, which includes rainwater management layers, root resistance, and a biodiversity-focused Bauder Flora 5 seed mix. This green roof not only improves rainwater retention but also supports local plant life. The use of VMZINC Plus standing seam cladding along planters and drainage outlets enhances durability and visual harmony with the natural surroundings.

Eco-Friendly External Walls and Sustainable Cladding
The walls of the new structure incorporate treated softwood battens with Douglas Fir plywood cladding, finished with Keim mineral paint. This breathable, long-lasting paint is ideal for listed properties, preserving the townhouse’s historic charm while offering weather protection.

Custom Joinery and High-Quality Doors
Our team created bespoke Douglas Fir doors and windows, featuring low-iron toughened glass to ensure optimal insulation and security. For added efficiency, Schlegel AQ21 weather seals provide airtightness, reducing energy loss. Yorkstone facings frame the thresholds, complementing the heritage elements with a durable finish.

Interior and Exterior Finishes
Inside, WBP Douglas Fir plywood lines the structure, treated with Rubio Monocoat Oil to enhance the wood’s natural grain. The floor features Yorkstone pavers and perforated clay brick accents, combining rustic durability with the extension’s eco-friendly focus. The servery area is finished with traditional encaustic cement tiles from Terrazzo Tiles, adding a rustic touch.

Energy-Efficient Mechanical, Electrical, and Water Management
The project incorporates low-energy solutions, including porcelain light fittings, festoon pergola lighting, and weatherproof outdoor sockets. Bauder Liquifibre roof upstands, threshold drains, and strategically placed gulley systems manage rainwater, directing it to planting beds to sustain the garden’s vegetation.

Sustainable Landscaping and Biodiversity
The landscaping design emphasizes biodiversity. We reused existing Yorkstone pavers and added slate stepping stones, creating a self-sustaining garden ecosystem. A custom pond, featuring natural boulder edges and native plants like hornworts, water irises, and flowering rushes, promotes biodiversity while creating a cooling microclimate.