Clad in american red oak panels built as ventilated structure which leaves a ventilated chamber between the coating and the insulation. The oak is treated with a diffusion open natural Mafi oil. The sink in solid oak is made from cut offs from the installation work, glued and pressed, and then CNC milled. The bathtub is made of cypress wood, untreated, and has a subtle sweet wooden scent when filled with water. The armature is made of brushed copper. The shower is made with standing oak lamellas for the water to run off easily and through a floor grating of oak. The shower is treated with diffusion open OSMO oil wax.


The bathroom is built as an experiment to prove the theory of hygrothermal mass, and no additional heating is installed in the bathroom. Explained in short; Hygrothermal mass is wood’s capacity to store energy, chiefly in the form of energy from moisture.


«We waste a lot of energy in the bathroom, often making it 3–5 degrees warmer simply because it feels cold when we step out of the shower with a damp body. But why heat the room all the time just for those few minutes when we get out of the shower? “If, instead, we have a bathroom where the ceiling and the walls are clad in exposed wood, we can use the energy that the walls and ceiling absorb when we shower to heat up the bathroom temporarily. Wood’s capacity to absorb moisture is enough to make the room at least two degrees warmer. So the room warms up at exactly the moment that people want it to, and for the rest of the time the bathroom can stay at the same temperature as the rest of the house.”  Dr. Kristine Nore PhD


The theory proves to work, after a warm shower or bath, the temperature in the room rises about 4-5 degrees, and stays warm for about 45 minutes. The floor feels warm when stepped on with bare feet due to low thermal conductivity in wood and hygrothermal mass due to moisture from the body.

Building category:
Material use:
CLT and oak
Delivery from Oslotre:
Interior design. Carpentry by Mikkel Solbjørg.