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Cladding and Curtain Wall Construction 431
Stone facing slab
Insulation between stone and
structural concrete. Spacers may be
used to maintain accurate fixing of
stone
Mechanical fixing bolt
Galvanised steel tie hooked to
upper slab
Stone slabs rebated to receive
hooked ties
Wire tie bolted to structural frame
Figure 7.13 Wire tie restraint fixing.
wire cramp may be used to hook an upper stone to those below, as illustrated in Figure
7.13. For brick backgrounds, a looped wire cramp is grouted into brick joints, with the
double toed ends of the wire set into holes or grooves in adjacent stones. An advantage of
wire cramps is that they can be bent on site to make an intimate fit to the holes or grooves
cut in adjacent stones.
Combined fixings
Combined loadbearing and restraint fixings combine the two functions in one fitting. Both
angle and corbel plate loadbearing fixings may be made to perform this dual function for
those slabs that are supported at each floor level. Dowels welded to the angle supports may
fit to holes or grooves in the stones they support and the top edges of the stones below.
Similarly, double hooked ends of cramps may perform the same function.
Stone bonder courses
To provide support for sedimentary stone facing slabs at each floor level, a system of stone
bonder courses at each floor level, supported by the structural frame, may be used.
A course of stones is bedded on a beam to provide support for the facing slabs to the
floor above, as illustrated in Figure 7.14. The bonder course of stones is of sufficient thickness
and depth to both tail back and give support to the facing slabs. Restraint fixings are
set into slot anchors cast in the beam and built into the brick background (Figure 7.15).
At the top edge of slabs and underside of the bonder course, a movement joint is formed
to accommodate relative movement of the structure and the slabs. A disadvantage of this