|
Strawbale
Building
Straw is a waste product.
It is inert, hard to ignite when
compressed, and of little interest to vermin as it contains
negligible amounts of food.
Foundations need to be raised to a
sufficient level to avoid the bales becoming damp but as long as
the straw is kept relatively dry it has a life expectancy
similar to conventional building materials.
Load-bearing strawbale
construction
In load-bearing strawbale buildings
the bales take the place of whatever normally hold up the upper
floors and the roof. As if they were part of a giant Lego set,
the bales are placed on top of each other in a stretcher bond
pattern. Hazel pins are usually then driven down through the
bales to provide a positive connection between the bales.
Non-load-bearing strawbale
construction
The other way to use strawbales is
to build a primary frame out of timber which accepts all of the
structural loads. The bales are then used to infill the panel
walls. This avoids the risk of compression of the bales but
still takes advantage of the excellent insulation properties of
straw.
In both cases the bales are then
covered with lime render. The use
of lime is important here as it is much more flexible than
cement and can accommodate minor movements. Lime render will
sometimes self-heal when cracks occur. It also breathes, which
is essential as moisture and other vapour must be allowed to
pass through the bales.
|
