The clients loved the site and the red barn is perfectly functional, but they asked Callaghan and partner Prue Johnstone to create extra – and genuinely comfortable – accommodation in the cowsheds. “The concrete was there as a ruin, and it had a monopitch roof sailing over it,” says Johnstone. “When we inherited the project, we didn’t want to go too far from that simple language – any insertion we made, we wanted to stay true to what was there.”

For Johnstone and Callaghan, the project was one of a trio of Covid-era, “barely there” projects – including a set of off-grid cabins at Waipara and a studio in the trees at Anchorage in Tasman Bay – where they created something special from a small footprint with lots of carefully considered, beautifully detailed moves. At Anchorage, it was a language of Corten steel, concrete and timber; at Waipara, it was an airy lightness. Here, the beauty comes from the interplay between old and new. 

Despite its charm, there was a forest of timber posts holding up the low roof, and almost no headroom at the back of the building. On the roof was an array of solar panels that powered the whole site. Pulling apart the shed would effectively make the place uninhabitable for as long as it took to build anything, and making an old open shed warm and dry ran the risk of eliminating everything that was lovely about it. As is so often the case with a ruin, its ramshackle nature was in direct opposition to its intended use.

Johnstone and Callaghan’s rough idea was to remove the roof and its associated timber structure, and build a new, bigger one over the top, held up by a lightweight but strong steel frame that allowed a much more open space below. Under that, they designed an entirely separate – and waterproof – three-room cabin with a bunkroom and two bedrooms; inside the original concrete shed is a bathroom and storage. “Even when we needed to enclose it, we wanted to keep that feeling of lightness, almost like a lantern effect,” says Johnstone.

After briefly considering prefabricating the cabins – as they had at Waipara – they worked closely with a local builder, Nick Shadbolt, to phase the project, rebuilding the roof and reinstating the solar panels, before they worked on the original concrete shed. They inserted polycarbonate panels between the original concrete walls and the new roof and into various holes in the structure, rather than plastering them up, allowing light into what had been a dark, damp space. There’s no attempt to cover up bumps, nicks and cracks, and you can read where old stops and new starts: there’s a painting on the back wall, cracks in the concrete; but there’s also new cabinetry, polycarbonate and galvanised steel. “Anywhere we did anything against the concrete, it’s very crisp,” says Callaghan.

Finally, they built the new cabin under the new roof. It’s respectful of the original concrete structure – silver steel panels on the outside and steel-framed windows reflect the grey of the concrete, and have an appropriately agrarian feel. The structures connect in exactly one place, where a galvanised steel portal punches through the original concrete wall and into one of the bedrooms, allowing for internal access to the bathroom.  

An original barn-style door inspired a second language of warmer timber tones for the interior – dressed macrocarpa cabinetry, birch-ply linings, band-sawn macrocarpa floors and similar barn-style doors. During the day, but especially at night, as the light fades and lights come on in the cabins, the effect is warm and inviting. “That big sliding door was part of what was there, which was brilliant,” says Johnstone. “We did everything we could to reinstate that, and it formed part of the language – it was a really nice touchstone to work with.”

Ask them what they’ve learned through such small, highly detailed projects and they both laugh. “That you can spend more time detailing one of these than you might a whole house,” jokes Callaghan. “Though really, it’s just that every single detail becomes important. In a house, they’re important, but you get to a point where there’s an expected way of approaching it. With these, at this scale? Everything is seen, and everything is considered.”