Fixings
Fyfestone architectural masonry provides an excellent medium for
many types of fixings and applications.
An important first consideration is to identify the type of
block and hence its compressive strength and configuration.
Another important consideration is the type of loads that the
fixing will be carrying. It may also be essential that the location
of the fixing into the masonry wall has to be accurately
established to avoid the mortar joints.
The chart opposite provides details on the types of fixings
suitable for all types of masonry units.
If in doubt, consult the fixing manufacturer for guidance on
their use, the type of products suitable for the application,
installation and their pull out values.
PLASTIC PLUG
Base of plug is expanded by the tightening of the screw (not
provided). Slim top portion prevents expansion in plaster. May have
lip at top to locate at the surface. Fins prevent rotation.
HAMMER-IN FIXING (plastic sleeved)
Screw and plug combined. Special drive screw can be hammered in
and unscrewed. Some have collapse feature to take up small gaps.
Collar and cross head screw give neat finish.
UNIVERSAL PLUG (plastic)
Various designs. A common feature is the ability to expand the
body against the sides of the hole in solid material or to pull
back against the back of a cavity in perforated or hollow
blocks.
SELF THREADING PLUG (plastic or zinc alloy)
The anchor is inserted into a predrilled hole using a crosshead
screwdriver. A coarse thread forms around the body to cut a thread
in the concrete material without inducing expansion stresses.
Available in nylon or zinc alloy.
THIN-WALLED SLEEVE ANCHOR (torque controlled expansion)
A through sleeve is expanded by the tapered end of the bolt or a
separate expander cone drawn into the sleeve on tightening.
Suitable for some perforated blocks as the expansion can be pulled
back into the block.
SHIELD ANCHOR (torque controlled expansion)
The large expansion ratio caters for the way holes may be opened
up oversize in weaker materials. Best in strong blockwork with
sound mortar joints. Diameters limited to M12, to avoid cracking
blocks.
BONDED ANCHOR USING INJECTION MORTAR
Stress-free fixings will not crack weak materials. Special
sleeves enable fixings in hollow blocks and perforated blocks.
Plastic sleeves usually have end cones for overhead use and
centralising the stud.
RUBBER EXPANSION ANCHOR
A rubber sleeve is expanded against the sides of the hole or
into a void by a nut bonded to the base of the sleeve. Equally
effective in a partial void.
WINDOW FIXING (steel screw with plastic sleeve)
Design similar to steel frame fixing. Cone is of glass
reinforced plastic. Lugs on sleeve locate the PVCU or aluminium
frame. In common with frame fixings, the frame is not pulled toward
the base material.
KEY:
M=Machine screw diameter
mm=Sleeve or body diameter
No.= Screw number
NOTE:
*Plastic is a general term which includes nylon