When you build
timber frame house, Both timber frame and brick
and block houses have an outer skin (usually brick)
and a cavity (usually 50mm). Where they differ is
in the construction of the inner wall.
With a standard timber frame this consists of a
waterproof membrane, sheathing board, structural
timber frame, vapour barrier and inner lining of
plasterboard. The insulation is placed between the
timber frame uprights, and its thickness matches
the size of the frame (usually 90mm). With standard
brick and block, the inner wall consists of aggregate
block and an inner lining of plaster. The
insulation is placed directly in the cavity,
which is either partially or completely filled.
The main difference
between the two types of construction is how the loads
of the house are taken. With timber frame, the frame
itself supports the weight of the house, while with
brick and block, both the outer brick and the inner
block take the weight.
A range of outer
claddings can be applied to both timber frame and
brick and block houses, including brick, stone,
render, hanging tile and timber boarding. With timber
frame the actual timber structure
is often exposed as a design feature.Windows in
timber frame houses are fixed to the inner timber
frame, rather than to the brick outer skin, which
results in a deeper external sill.
With brick and block,
dummy timber posts and beams can be added to masonry
walls. These are not structural, but can look just
as authentic.
Both timber frame and
brick and block houses have to comply with energy
efficiency targets set out by the Building Regulations.
The minimum U-value (insulation level for each component
of the build) required for exposed walls is 0.45 W/m2K.
A standard brick and
block house offers a U-value of 0.43 W/m2K. Whereas
a standard timber frame outperforms the mandatory
ratings, achieving a U-value of 0.41 W/m2K. The latter
can be improved to 0.29 W/m2K by increasing the frame
size from 90mm (standard) to 140mm (enhanced), which
increases the space for insulation. This gain is at
comparatively little extra cost.
