Because of the need to reduce energy use it has become
necessary to construct super- insulated or low energy homes.
The dimensions of contemporary and timber/steel timber
frame walls are usually governed by structural needs, but the desire to
incorporate still more insulation has led to the development of a double wall
system - one at the outside and the other at the inside of this wall. Using a
spacer block, walls of various depths can be achieved for any desired u-value.
In this way, walls of almost any depth can be built without adding
significantly to the cost of framing.
With our system, thermal bridging is reduced to a
minimum, with only 2 points of contact, depending on wall heights.
Structurally, the walls are still the same as conventionally designed frames
but with minimal thermal bridging and an increased thermal mass.
By increasing the depth of the walls to suit
readily available insulation depths, the u-value can be increased without any
structural issues. The air-barrier is located on the inner wall and a 50mm
insulated service cavity is provided for electrical, heating and other
services.
Our standard low-energy wall consists of 300mm of high-density
fibreglass, 50mm high- density fibreglass in service cavity giving a u-value of
0.117 W/m² k. For a fully breathable wall option and a slightly better u-value,
we can substitute the 9mm OSB 3 sheeting on the exterior of the wall with a
22mm wood fibre sheeting together with hemp/ or wood chip insulation.
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Double Wall System 
