in 1998, Jan Sonneveld has done a great job in realising
his dream, an ecologically friendly house. One of the main
challenges met was the exceptionally wet summer. Due to
various reasons the initial lime plaster was a complete
failure. (using already hydrated lime is important) The
lime stucco was completely removed and replaced with clay
plaster. Since then a lot of effort has been spent finding
a solution to prevent moisture penetrating the plaster in
less well protected areas of the walls.
first attempt to protect the plaster with a whey wash was
a failure. In some of the more critical areas moisture levels
went far over acceptable levels (40%) and most of the whey
was washed off in the heavy rains. A second attempt in the
summer of 1999 was much more successful. This is a short
(edited) report by Martin
Oehlmann on the findings:
the whey-lime wash performs extraordinary well on the clay
walls exposed to rough weather. Whey has been added to the
lime instead of water. We tested an area by spraying it
for 1 hour with a hose. There was a 0% increase of humidity
measured over a period of days. Some miniscule particles
of the whey-lime wash protection have been washed away most
probably due to the water pressure. Therefore the end of
October 1999 we will brush on a second layer on the weather
side to really make sure no water penetrates the walls."
then this unprotected wall has been given a proper roof
Jan Sonneveld passed away in March 2001 after fighting cancer.
Happily his pionering work is being followed up by his son,
and his son's wife, Saskia, who now occupy the home. Jasper
and Saskia are now completing the dream as set out by Jan.
Besides some modifications to suite the purposes of a young
family they are spending a lot of effort in creating a permaculture
about the Butterfly House can be seen here on the Dutch
straw bale-foundation website.