LITTLE CUTMADOC

Our extension to a traditional Cornish farmhouse near Lanhydrock Estate transforms a modest lean-to into a striking two-storey addition that opens the home to its woodland setting and lake views. The ground floor stone-clad volume houses a family living space, WC, and utility, while the cantilevered cedar-shingle master suite above enjoys a private rooftop terrace and panoramic countryside vistas.

Built using carbon-neutral timber frame construction with wood fibre insulation and airtight detailing, the extension exceeds Part L requirements and eliminates cold bridging. Bronze-finished triple-glazed windows and a restrained palette of natural materials blend the building into its surroundings.

Environmental protection was paramount, with robust site strategies safeguarding a nearby koi pond during excavation. Innovative roof detailing and moisture modelling enabled a breathable, thermally robust flat roof terrace. The result is a light-filled, low-energy home that connects seamlessly with its landscape and offers lasting comfort and ecological integrity.

The brief was to provide additional relatively modest living space, whilst also opening up the house to the surrounding gardens and maximising views of the adjacent lake and countryside beyond.

The design reimagines a traditional Cornish farmhouse through a contemporary yet sensitive two-storey extension that embraces its woodland and lakeside setting. A stone-clad ground floor anchors the building within the landscape, providing family living spaces and practical amenities, while a cantilevered cedar-shingle master suite above captures panoramic countryside views from a private rooftop terrace. The architectural language contrasts solidity with lightness, creating a seamless dialogue between the old and new.

Built using a carbon-neutral timber frame with wood fibre insulation and airtight construction, the extension achieves exceptional thermal performance and eliminates cold bridging. Natural materials, including bronze-finished triple glazing and cedar shingles, ensure visual harmony with the surrounding woodland. Environmental care guided every stage of design and construction, from protecting the koi pond during excavation to developing a breathable, moisture-safe flat roof terrace. The result is a sustainable, low-energy home that balances comfort, craft, and connection to nature.

The extension was constructed using a carbon-neutral timber frame system designed for exceptional energy efficiency and environmental performance. Wood fibre insulation and airtight detailing ensure a breathable yet highly insulated envelope, exceeding Part L requirements and preventing cold bridging. The ground floor’s locally sourced stonework provides durability and a visual connection to the original farmhouse, while the upper level’s cedar shingle cladding offers warmth, texture, and natural weathering qualities.

Triple-glazed bronze-finished windows enhance thermal performance and complement the building’s refined material palette. A carefully engineered flat roof supports a private terrace, with innovative moisture modelling ensuring longevity and protection in Cornwall’s variable climate. Construction was carried out with great sensitivity to the site, including measures to safeguard the existing koi pond and surrounding woodland. The result is a robust, low-energy extension that unites traditional craftsmanship with modern building technology.

Low carbon, sustainable building materials were used throughout the project where possible. The structure was built using an externally insulated (carbon neutral) timber frame construction, allowing for enhanced levels of thermal insulation over and above Part L requirements. The construction was made as airtight as possible by using a combination of intelligent Pro-Clima air tightness tapes and membranes as well as certified airtight internal sheathing boards. All timber frame insulants used were wood based, and densely packed to fully fill the structural voids as well as being externally insulated with 60mm wood fibre t&g boards to eliminate all cold bridging through the frame thus reducing the risk of a significant “performance gap” between design and as built construction.

The project used a restrained pallet of natural materials externally, predominantly stone cladding to the ground floor, with the upper cantilevered bedroom being entirely clad in cedar shingles, both wall and roof. This mix of two materials, stone and cedar shingles, keeps the architectural language simple and easily understandable. The ground floor box of stone, closely links with the existing stone cottage and integrates the extension into the surrounding landscape on various levels. The upper cantilevering first floor bedroom is entirely clad with natural, untreated cedar shingles and occupies the space of the surrounding tree canopy above. These long-lasting aluminium triple glazed windows in a textured bronze finish were chosen to compliment this aesthetic and in time blend seamlessly with the cedar shingle façade as it begins to patinate over time.

Although utilising more natural, textured materials, modernist detailing was considered throughout, integrated hidden roof gutters, minimal glazing sight lines, recessed glass balustrading, flush skirting internally with shadow gaps carefully aligned through with window boards.

Perring Properties, as the principle Contractor, completed the initial health and safety file, producing a robust site health and safety folder during the mobilisation stage and before works commenced on site. However, unlike their other sites, this extension was located directly adjacent to a large pond which contained a huge amount of treasured koi carp. Additional measures were therefore put in place to ensure that the watercourse could not be polluted as a direct result of their works. This included sandbags along the driveway to divert surface water washing mud into the pond during the excavation phase where over 300 tonne of spoil was removed; a boom was installed across the pond to contain oil spills should they have occurred and the site compound was positioned at the furthest point away from the pond. Sub-contractors were informed of this strategy during their inductions then reminded of them during the tool box talks. The systems put in place and due diligence of all operatives ensured that the watercourse was not polluted and ultimately no koi carp were harmed during the works.

• Ground floor U-Value – 0.12W/m2k
• Timber Frame Walls U-Value – 0.20W/m2k
• Timber Frame Pitched Roof U-Value – 0.19W/m2k
• Flat Roof U-Value – 0.11W/m2k

The non-standard roof construction required detailed thermal analysis to avoid the potential for any interstitial condensation occurring. External experts, Ecological Building Systems, were brought on board to carry out detailed WUFI calculations to ascertain the moisture risk to the roof construction and offer advice on recommended roof build-ups. This led to a relatively innovative flat roof terrace construction being proposed, with full fill wood fibre based insulation tightly fitted between roof joists and 100mm PIR insulated roof over the top all combined with an intelligent internal airtight vapour control layer which mediates moisture control throughout the year.