This is the first modern example of a designed moisture transfusive building. The technique has become increasing common over the last 25 years because of well-recognised benefits in relation to the indoor environment.
The 210m2 wood and stone pentagonal house was designed and built by Dag Roalkvam and Rolf Jacobsen for their final year thesis. Dag and Rolf were students of Howard Liddell then Visiting Professor of Building Technology in Oslo. With others in their cohort, they became founder members of Gaia Norway, in 1984.
The building was constructed in keeping with the Gaia architectural philosophy, avoiding the use of materials known to contain toxic substances. It is zoned for temperature with warm rooms facing south and cold rooms facing northwest in. It has a double skin. A timber rain screen hangs 600mm away from the walls on the weather facing sides. This 'sacrificial' outer skin protects the walls from the prevailing wind and is broken by gaps for light and views.
Moisture transfusive construction is a strategy that contributes to maintaining a balanced relative humidity It is often mistakenly called a 'breathing' wall – which gives rise to confusion about the nature of flows across the fabric. They are more accurately 'sweating constructions' and the concept is most simply understood by comparison with the human body. Skin is porous and we are most comfortable in clothing that allows moisture to pass through it. Similarly the ability of a building to allow and encourage moisture to move from inside to outside in response to a vapour pressure gradient is intensely practical. It also enables a reduction in mechanical systems that would be required to maintain acceptable relative humidity. It relies on surfaces having permeable finishes.