 History of wall tie
corosion
Cavity wall design
incorporating metal wall ties, has been in use since the
beginning of the nineteenth century, to prevent rain
penetration and to improve thermal
insulation.
Over recent years, it has become
apparent that a high number of properties, built before
!981 are suffering from premature wall tie corrosion.
Latest research by the Building Research
Establishment, has found that wall ties corrode faster
in the mortar within the external leaf of brickwork,
leading to lamination where they will expand to several
times their original size.
This expansion will
cause structural instability, by lifting the mortar
Joints where they lay. Visual evidence of corrosion can
be seen by horizontal and diagonal stepped cracking to
external wall surfaces. If corrosion is severe it will
lead to distortion and bulging. In some cases external
walls have collapsed during gales. Research has also
found that a high percentage of properties inspected,
had an inadequate number of wall ties especially around
openings, i.e. windows and
doors. |
We have a range of solutions from
HELIFIX for various applications and wall
types.
Retro Tie
RetroTie is a simple but very effective stainless
steel remedial wall-tie engineered specifically for the repair
and reinforcement of defective walls. The RetroTie wall tie
system is versatile, easily installed and has been
comprehensively tested and proven.
A unique development,
RetroTie is a helical fixing that is hammered into position,
with excellent results in both masonry-masonry and
timber-masonry cavity walls.
RetroTie provides the ideal
solution to defective walls with corroded ties and split
mortar beds or requiring extra ties for other reasons.
RetroTies prevent wall movement from wind loads whilst flexing
to permit natural expansion and contraction of wall materials,
without creating stress.
DryFix
The DryFix
technique for tying multiple layers of masonry involves simply
driving a specially formed helical tie through the masonry,
via a small pilot hole, using a unique installation tool. The
DryFix tie self-taps into the masonry to provide a solid
fixing in both leaves without mechanical expansion or any need
for grouts or resins.
Engineered from Grade 316 austenitic
stainless steel, DryFix one-piece ties are extremely quick
and easy to install. They are suitable for use in all
normal cavity and solid masonry construction and have been
designed to be driven through, and into, brick, block,
aircrete, concrete, strong mortar and timber to provide an
effective and highly economical repair solution. They can also
be installed through insulation without impairing its thermal
properties.
DryFix ties are used to re-stabilise cavity
walls suffering from wall tie failure or omission and to
repair solid masonry which has become delaminated for various
reasons including collar joint failure and broken headers. The
system may be used in high rise, domestic and commercial
buildings with the spacing being varied to meet the actual
loads being imposed on the building.
No expansion
pressures are created during installation so DryFix ties may
be used in hollow materials and close to edges without risk of
splitting the material. The ties are sufficiently flexible to
permit normal masonry movement, are designed to shed water in
cavity construction and yet provide strong axial restraint in
both tension and compression.
|
 Above shows the process of pilot drilling,
inserting wall tie and making good the exposed
hole. |
|
