The Cornish Coach House We Designed but Never Built

Some of our favourite designs have never been built, and this piece of interior design in Cornwall is one of them.

At the bottom of the garden of a Grade II listed manor house in south-east Cornwall sits a stone coach house. When we first saw it, part of the roof was missing. Water had been getting in for years and one ceiling had already come down. An earlier attempt to patch the roof had made things worse.

We had already spent several years on the main house. That was a full transformation of a listed home with more than 25 rooms, each with its own identity. The coach house was going to be the second chapter: a four-bedroom guest house in the grounds. We designed it, went through the bat surveys and listed-building conditions, and produced a full set of visuals. Then the project paused before the build began.

These are the images, and the thinking behind them.

The brief: a quieter cousin to the main house

The main house is joyful and full of colour: hand-painted wallcoverings with native Cornish butterflies, local artisan tiles, a sunny orange study. We always wanted the coach house to be calmer. The brief described it as “a slightly more modern and less ornate cousin” to the main residence: light, warm colours, simpler detailing, and the stone and timber of the building left to do the talking.

It also had to work for guests who would arrive muddy from a walk, want somewhere to sit by a fire, and sleep somewhere quiet. So the plan started with the boot room, not the bedrooms.

Joining two buildings with glass

The site has two old buildings: the coach house itself and a stone barn beside it. Rather than build a big new extension, we proposed linking them with a glass box. You arrive through the glass link, drop your boots and coats in the boot room, and step into the lounge.

The glass does two jobs. It keeps the historic stone of both buildings visible, so the new part reads as a light touch rather than a third building. And it opens the whole route to the trees around it, so walking from one wing to the other feels like walking through the garden.

The rooms

• Kitchen and dining. With the bats rehoused, we could open the ceiling up to a vault. Dining for eight to ten around an open fire, because a guest house in Cornwall needs somewhere to gather when it rains.
• Lounge. Large double-aspect doors and a fixed-panel window to pull in the light and the view.
• Library and study. A small room for quiet, with a guest WC nearby.
• Upstairs. Two modest guest bedrooms and a family bathroom, simple but true to the building.
• The west wing. The barn becomes two grand bedrooms, one with an en-suite and a view into the woods, plus a private courtyard seen only from those rooms. The plant room sits here too, out of the way.

Bats, slate and listed-building consent

A listed outbuilding in the countryside comes with rules, and most of them are there for good reason.

Bats. The coach house was home to bats. That meant surveys, a mitigation plan and a licence from Natural England before any roof work could start, with monitoring to follow for years afterwards. Repairing the roof properly was part of the licence, not just the design. It also explains the vaulted kitchen: once the bats were rehoused in the main house loft, the ceiling could open up.

Slate. The plan was to save and reuse every slate we could. Cornish Delabole slate was the natural choice for the rest, but new slate had a long lead time (around 18 months when we checked) and a high cost, so we looked at alternative stone slates as well.

Detail by detail. The council needed to approve the timber repairs, roofing felt and fixings, slate coursing, hips and ridges, leadwork, chimneys and replacement ceilings. Joining the buildings and changing the inside needed further consent. We also planned to repair timber rather than replace it wherever possible. That is both better conservation and, usually, better carpentry.

Making it safe first. Before any of the design could happen, the first job was to strip out the damaged interiors, make the building weather-tight and have a structural engineer check the floors.

The outside

We kept the exterior quiet and local. Windows and doors in a soft green (Farrow & Ball’s Card Room Green), cast-iron half-round gutters and bronze exterior lights that will age well in the salt air. At the front, square stepping stones in beige and brown tones set into fine pebbles, so the path looks like it has always been there. The lounge windows lose their curved tops in the new design, to sit more simply against the stone.

Interior design in Cornwall, from a London studio

Working on a house a long way from the studio changes how you run a project. A few things we learned on this one:

• Use local trades where you can. Roofers, gardeners and specialists who know the area, the weather and the planning officers save time and trouble.
• Plan site visits around the trades. Every trip needs to count, so we build visits around inspections and key stages, not just progress checks.
• Weight costs money. Heavy materials like tiles and stone are priced for delivery by weight and distance. That shapes what you specify.
• Design for the weather. The site is windy enough that bins blow into the field. We designed a sheltered bin store. Small details like that matter in the countryside.
• Think about the water. Old rural properties often have private supplies. A house that has stood empty may need its water checked before anyone moves in, and a borehole can be worth keeping for the garden in a hosepipe ban.

What happens next

The coach house is still standing, still beautiful and still waiting. We’d love to finish what we started. Until then, the visuals are a good record of how we approach a listed building: respect what’s there, add as little as you need, and make the new parts quiet enough that the old ones can shine.

You can see the finished main house in our Cornwall manor house project, and read how we opened up its living spaces. So if you have a listed home in Cornwall or the South West and are thinking about interior design for what comes next, we’re always happy to talk about projects outside London.