Most insulated concrete block systems
consist of lightweight concrete
blocks whose voids are filled with rigid
foam. But one of the most intriguing
new systems uses no foam at all. The
Hebel Wall System consists of solid aerated-
concrete blocks (made from sand,
cement, lime, and an expanding agent)
that are as strong as concrete at onefifth
the weight. And an 8-inch Hebel
wall has an overall insulating value of
R-30. Hebel blocks are laid up with
thinset mortar and require no surface
bonding. The lightweight blocks can
be sawed, nailed, and routed with normal
woodworking tools.
Hebel built more than 70 homes in
the Southeast last year at an average
cost that was 2% higher than a