Garden saunas for Rwandan terraces and gardens

Standing on a slope

On a terraced plot we set the cabin on galvanised steel posts bolted into the stone retaining wall, with the floor frame levelled above the fall of the ground. It keeps the timber off wet laterite, it lets water run underneath in the March-April and October-November rains, and it means we are not cutting a new platform into a terrace that is holding the garden up.

Where the terrace is already built and level, a basalt or brick plinth is cheaper and looks better. We decide that on the site visit, with a laser measure and a photograph of the retaining wall — not from a plan.

Rain, sun and what the cladding has to survive

Rwanda gives a cabin two heavy rainy seasons and strong equatorial sun in between. We build the outside as a ventilated rainscreen: cladding, a drained cavity, then the insulated hot-room box. The cavity is the part people cannot see and the part that keeps the cabin alive — water that gets past the boards runs out at the bottom instead of soaking the insulation.

Cladding is a style choice with a maintenance consequence. Charred timber in the shou-sugi-ban tradition is our lowest-maintenance finish and it looks deliberate against red brick. Pale thermo-aspen is warmer and lighter but wants re-oiling every couple of years on the sun side.

Where the door faces

We point the door at the view and away from the prevailing rain, then put the cold plunge within three or four steps of it. The walk between hot and cold is the whole product — if it is long, wet and awkward, people stop doing it after a month.

In short

• Galvanised steel sub-frame into the retaining wall on sloped plots
• Ventilated rainscreen cavity — the reason the cabin survives two rainy seasons
• Charred timber for low maintenance, pale thermo-aspen for warmth
• Door and plunge placed so the hot-to-cold walk is three or four steps