Cavity Wall Ties
Cavity wall construction has been adopted since the beginning of the 20th century and offers better protection from the elements, as well as reducing the amount of heat loss unnecessarily from a building.
This form of construction comprises of two separate walls connected together at strategic intervals using a metal bar (wall tie) usually made of metal, coated in bitumen or zinc. In the 1980s it became apparent that the wall ties deteriorated much rapidly that expected leading to wall tie failure, thus the need arose for replacement cavity wall tie systems.
We have fully trained and experienced Structural Surveyors who have a range of solutions at their disposal from Thor Helical Remedial to solve your cavity wall tie problem. Our Surveyor will recommend the most suitable structural repair for your property as well as providing a written report for the work to be carried out.
In order to assess existing cavity wall ties we use various types of specialist equipment. High quality metal detectors are used to locate the wall ties within the cavity walls.
After location the condition of the wall tie is assessed using fibre optic boroscopes.
After assessment of the cavity wall ties a specification for remedial works if required is produced.
In general terms the remedial work is dependent on the severity of the problem and the specific type of wall tie within the building. We have an extensive range of high quality stainless steel remedial wall ties to suit almost any application.
Replacement Cavity Wall Ties
Remedial Cavity Wall Tie Systems can be employed to reinstate stability to existing walls; damaged by expansion of corroding mild steel vertical twist ties; loss of wire ties by corrosion; insufficient ties; ineffective ties and or unrestrained masonry.
The choice and validation of a suitable remedial wall tie system and their density must provide for fixing in both inner and outer leafs required by the imposed loads and conform with BRE Digest 329, 401 and BS 5628.
All the remedial wall ties we install are manufactured from 304 or 316 stainless steel.
Testing should be undertaken as a minimum on one or two fixings to each elevation to determine the minimum pull load obtainable from both leafs. On large projects 5% of ties should be tested as part of the installation routine. The tensile load results should be used to determine the suitability of the fixing and density in accordance with BRE Digest 401.
Selection of Replacement Wall Ties
Drive Fix Ties – For rapid cavity wall tie replacement & brick pinning, stainless steel helical wall ties are the choice of the professional for tying masonry walls.
Self tapping 9mm replacement cavity wall ties screw into brick, masonry or concrete when hammered into pilot holes (circa 6mm) using the impact action of a hammer drill. The Thor Helical Drive Tie grips within an interlocking helical undercut.
Stainless Neoprene Expanding Ties – Replacement wall ties for cavity walls. Quick-Fix mechanical tie has durable neoprene expansion sleeves at each end of an Austenitic Stainless Steel bar.
The Quick-Fix replacement wall tie features a unique part threaded tall-nut which when turned, rotates the bar, forcing open the Neoprene sleeve to grip the remote masonry leaf. At a factory set torque level, the bar taps a thread in the top of the tall nut to force it down the bar, expanding the near leaf to grip the wall.
Resin Bonded Wall Ties – Resin bonded ties are widely accepted to provide a good fixing to most substrates, ideal for where the quality of the substrates is in doubt. The Thor Double Resin Tie manufactured from 5mm Austenitic 304 grade stainless steel bar has a thread at each end with a nut to centre the ties in place and retain the resin and a neoprene drip.
All bars are 5mm thick and come in 175mm, 200mm and 225mm lengths; these can be used with either Polyester Resin or Epoxy Acrylate Resin.
Thor Helical Grout Ties – Grout ties are a combination of Thor Helical W60 Flexi Grout and Stainless Steel Heliforce Bars, delivered together to provide a quick, simple and cost effective masonry repair technique with minimum disturbance.
Thor Helical Remedial W60 Flexi Grout – A high performance masonry grout. A cement grout / polymer blend supplied in a bucket for mixing.
Consists of a powder component and liquid component, which when mixed together provides a pumpable thixotropic masonry grout.