Foundation walls now in place.
Posted from: MD, USA
Foundation walls are now up, and the construction forms are off. Next
steps will be waterproofing the exterior of the walls, then applying
the underground insulation and drainage board. Tammy Fuller from
Mid-Atlantic Foams was at the site measuring for insulation quantities
when I visited and left us a sample of the insulating drain board (see
This two inch thick board is designed to provide a “drainage plane”
for the wall, creating a capillary break and channeling any water that
gets to the wall down the face of the wall and into drains placed at
the footings. It is composed of small foam balls which allow the
passage of water. It is coated at its outside face with a layer of
fine mesh (“geotextile”) which allows the passage of water but keeps
dirt out. In our case this 2” board will be laminated to a another 2”
thickness of expanded polystyrene insulating board designed for
Creating a drainage plane in this way is not particular to Passive House construction; it is simply standard good construction.
The walls from above and from inside basement.
The insulating drainage board.
Brendan O’Neill, Jr., Tammy Fuller, and Keith Kauffman