Civil Engineering Reference
In-Depth Information
compression timber. Lay the polyester strapping over the compression timber in the
window opening and tighten the straps using the tensioning tool to compress the bales
below. If possible, when tightening the straps, keep the compression timber horizontal
and parallel to the bales. Use a spirit level during this process to monitor the horizontal
status of the timber. While it is desirable, it is of no huge concern if the compression
timber does not end up level. To overcome any variance, insert packers between the
underside of the sill of the window buck and the compression timber to bring the sill
timber into a level position. It is more important that the bales below the window are
compressed than the compression timber held level. However, be vigilant to ensure that
the timber is kept in the correct position horizontally on the bales as this is the
foundation on which the buck will be fixed.
Fit the window buck on top of the compression timber, ensuring that the sill of the
buck is level and the stiles are vertical relative to the face of the wall. It will be necessary
to place temporary braces from the top of the window buck down to the floor or to pegs
in the ground to hold the window buck in a vertical position while the bales are laid
around it.
Check that the buck is plumb and level within the straw bale wall. Because diagonal
bracing has been fitted to the face of the window buck, when the sill of the buck is level,
the stiles of the buck should be vertical or plumb. Do not however take this for granted,
check it. If this is not so it is likely that the diagonal brace is incorrectly positioned and
should be altered before bales are laid around the buck.
When the window is eventually fitted, it is essential that support be provided below
the line of the actual window to all vertical members of the window. Therefore it will be
necessary to provide packers between the compression timber and the sill of the window
buck to line up with the stiles of the actual window when eventually fitted. Apart from
the stiles of the window which are at the outer line of the window, the mullions must also
be supported. (The mullion is the vertical piece of timber within the body of the window
that forms part of the fixed frame of the window.) Fit the required packers between the
compression timber and the buck sill, fixing them in position to avoid dislodgment.
Window bucks greater than 900 mm wide without bales above the window
where no lintel is required
The procedure for this window buck varies only slightly to that of the window buck up to
900 mm wide with bales above it. In this form of construction it will not be necessary to
fit a second head on the top of the window buck, as the window head is not carrying the
load of bales above it. There will be a gap between the underside of the bale boxing and
the top of the window buck. This gap will allow the top boxing to drop without fouling
on the window buck during compression of the wall.
The infill structure above the window
The bales are to be compressed over three days to gain maximum compression, following
which the framing over the window will be completed. The framing over the window is
referred to as a dropped rolled head. As the name implies, a dropped rolled head would
normally have a rounded appearance over the window however it is possible to create
