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434 Barry’s Advanced Construction of Buildings
Thin slab of facing stone
Insulation between stone and
structural concrete. Spacers may be
used to maintain accurate fixing of
stone
Mechanical fixing bolt
Bolt head and washer
Pellet of stone fixed in hole to cover
bolt head
Expanding bolt mechanically fixed
in drilled hole – alternatively a
chemical resin anchor bolt could be
used
Figure 7.16 Face fixing for stone cladding.
The holes drilled in the stone for the bolts are then filled with pellets of stone to match the
stone of the slabs. Joints between stones are filled with gunned-in mastic sealant to provide
a weathertight joint and to accommodate differential thermal and structural movement.
The bolts must be of sufficient size, accurately set in place and strongly secured to the solid
backing to prevent failure of the fixing.
Soffit fixings
Support and fixing of stone facings to soffits is effected by the use of hangers and plates,
cramps or dowels that are suspended in slot hangers cast in the structural soffit. Stainless
steel or bronze channels are cast into the soffit of reinforced concrete beams and slabs to
coincide with joints between facing slabs. Hangers fit into the lipped channel to allow for
adjustment of the hanger to suit joints in stone soffit. With the system illustrated in Figure
7.17, the plates supported by the hangers may be cut to fit into grooves or slots cut in the
edges between stones, or be made to fit into slots cut in the edges of four stones, depending
on the thickness and weight of the stone slabs used and convenience in fixing. The number
of hangers used for each soffit facing slab depends on the size and weight of each slab and
the thickness of the lipped edge of the slab bearing on, and therefore carrying, the slab. At
the junction of soffit slab, and wall slabs, a hanger bolted to the wall background may have
a lip or stud to fit to slots or holes in the edge of the soffit slabs.
Joints between stone slabs
Joints between stone facing slabs should be sealed as a barrier to the penetration of rainwater
running off the face of the slabs. Where rainwater penetrates the joints between stone