Civil Engineering Reference
In-Depth Information
render. Apart from being unsightly,
the separation cracks between the
timber windows and render are
likely to cause a thermal bridge in
the walls, allowing heat transfer as
well as the possibility of water
penetration.
This system is similar to that of
the window treatment of a
weatherboard house with one
variation. The horizontal architrave
at the top of the window in a
weatherboard has metal flashing
fixed to and over the front edge of
the architrave. The other end of the
flashing is then tucked under the
lower edge of the weatherboard
above, giving it a total weather seal.
This is not the case with straw bale
construction. With straw bale construction the joint of the render to the top architrave
will be relied upon to seal the junction. While I am confident about the stability achieved
by the application of sand and glue at the junction of timber and render, it does have
limitations. I feel that it would be irresponsible to suggest that this seal would be
sufficient to turn away water if the seal were of a horizontal nature (see Figure 10.6). If,
however, the render were to extend over the face of the architrave, this would dramatically
increase the likelihood of success (see Figure 10.7).
Figure 10.5
Architraves at the stile of the window to conceal the
junction of the window and the render
Figure 10.6
Render that finishes on the horizontal
surface of a window head architrave is likely to result
in deterioration of the render at that junction
Figure 10.7
Render that finishes on the vertical face
of the window head architrave will discharge water
cleanly from the render
