With no building experience and wanting something light on the land, they installed screw piles and an insulated prefab panel for a foundation and subfloor. For the walls they mixed hemp, lime and water to create a hempcrete mortar. With the help of family and friends, they finished building and drying the walls in three months.

Hempcrete serves as a good insulator, so even though temperatures often drop below freezing during winters here in the foothills of the Pyrenees, the couple doesn't need any heating system. The home takes advantage of the sun's heat by being oriented toward the south for maximum solar gain during the day and the concrete floors trap that heat to be released throughout the evening. If there is ever a particularly cold night or days without sun, the couple installed a wood-burning stove to bring up the indoor temperature by a few degrees, but not much is needed, even in those circumstances.

Given the chronic drought in the region, Olivia and Nil installed a worm composting toilet. Other than the urine-separating element, it looks like a standard toilet, and only needs to be emptied of finished compost every two years.