BRICK REVIVAL LTD. T/A GUN-POINT – PORTSMOUTH
History of wall tie corrosion
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.
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.
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.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.