Garden Hide is a labour of love and learning for Commonbond Architects

The Garden Hide is many things to architects Kate Nicklin and Graham Mateer. It’s their place of work, the first home of their young practice Commonbond Architects, and soon perhaps their own home – temporarily – while they redevelop the tiny southeast London bungalow in whose garden it sits. More than that, at the self-built studio they have honed their own practical skills and refined their thinking about sustainable design, so it now stands as a statement of intent for the way they hope to practise.

The couple had development in mind when, as project architects with 10 years’ experience at other firms, they bought the bungalow. ‘We were always doing things on skinny little sites so we saw the potential,’ says Nicklin. At 29m² the garden building is only slightly smaller than the 36m² house. In plan it has two main rooms separated by a thick spine wall, so could easily be divided in half if and when the bungalow is replaced with a pair of semis, for which they have consent. 

A garden room could have been built under permitted development, but because the architects wanted to dig down 1m to increase the interior volume and give views out through eye-level flowerbeds, they put in a householder application. To keep options open, planning drawings amounted to little more than the most gestural squares and rectangles, says Mateer. In fact, they didn’t draw the building fully until after it was complete, working instead from sketches, evolving the design as they built.

A decision taken even before the final form of the building was worked out was to use hempcrete, and the pair have become enthusiastic advocates for the biocircular material. Combined with a timber frame, it provides structure, breathable insulation and fireproofing, and is so easy to use that the architects could draft in equally unskilled friends to help, making for sociable construction.

Outside, the vegetal walls are coated in thick gobs of lime render flicked on with a paint scraper and finished with many thin coats of chalky limewash. Laborious but economical, says Mateer, and another pragmatic choice for people with little hands-on building experience. It gives the small building with its overhanging, monopitch roof a soft but weighty character quite distinct from a typical garden shed. Rustic roughness is also melded with some refinement: oak-framed windows – with triangular mullions inspired by a medieval house at the Weald & Downland Museum – are beautifully made, again by the architects. 

Even so, stepping through oak doors at either end brings surprise. Daylight fills the sunken rooms through garden-facing windows, set above built-in bench seating, from which ribbed oak wainscotting extends around the base of subtly textured painted hempcrete walls. Reflections from a pond dapple the soffit of the overhanging roof outside – a deliberate recreation of the effect produced by puddles on the balcony of the couple’s last flat. Small windows in the back wall are placed on the outside face to make the best of the west light. 

One room is set up as a calm kitchen-workspace and the other is a cosy living area; a platform bed sits over a small bathroom with a composting toilet, tucked behind the freestanding hempcrete chimney of a wood-burning stove. Here, the structure is left unpainted to reveal its natural grey colour and day-joints between six separate pours. Each is around 600mm deep – an arm’s length, and thus the furthest a builder can reach down into shuttering to tamp down the mix. 

Fine finishes elsewhere belie diligent frugality. Cover strips in the wainscotting are offcuts from the angular mullions. In an imaginative bit of upcycling, solid Elm flooring was made by running Ercol table-tops through a planer-thicknesser. Not the fashionable mid-century modern stuff, Nicklin hastens to explain, but hefty dark-stained refectory tables picked up cheap on Facebook Marketplace. Waste was given to a wood-turner friend, who reciprocated with custom-made door handles. Sliding shutter gear was fashioned from Ikea toys. Brass plates that protect the timber steps at each entrance were bought for a couple of pounds from Ebay and carefully patinated with salt and vinegar. 

Of course the project cost of just £22,000 is largely down to the pair doing all the work, which took about two years. ‘For months I had the same answer every time someone asked about weekend plans,’ says Nicklin. ‘Digging a hole.’ In part, the slow pace was down to inexperience. ‘We spent an inordinate amount of time on YouTube, learning how to do things,’ says Mateer. But they also enjoyed switching between thinking and making as the project progressed, revising it as they went. ‘That slow design process is something we are now trying to do with clients,’ says Nicklin.

Other valuable lessons came out of the build. Handling materials gave better appreciation for how much is really needed. Avoiding dust inhalation when cutting PIR roof insulation firmed up the practice’s conviction that it should embrace natural building materials. And the project prompted a rethink of plans for the bungalow. A hempcrete-heavy refurb might be the way to go, although replacement remains a possibility. The question is how to finance a slow self-build. Developers have advised flipping the consented scheme with a quick sale, but when the suggestion is aired in the quiet studio it seems almost sacrilegious. This labour-of-love project has come to represent a different kind of investment.