External cracking to buildings of cavity construction is often due to failure of the existing cavity wall ties. It is frequently found that corrosion of the cavity wall ties and/or the lack of wall ties installed during the construction stage is the cause of the damage.
Investigating and Resolving Wall Tie Problems
Falcon Structural Repairs can carry out physical investigations into the cause of crack damage within various structures and recommends suitable remedial measures.
Falcon’s investigative techniques comprise an initial visual survey to determine the extent of the damage and the probable cause. A Cavity Wall Tie Detector is used to locate the existing metal ties, which are then physically inspected using an “Endoscope” to check for damage.
Where corrosion of the steel wall ties is detected, an accurate estimate for the cost of remedial repairs can be produced.
Repair Methods
Falcon carefully cuts out and removes these corroded ties and can offer a variety of replacement wall tie methods, which can include mechanical wall ties and epoxy resin bonded wall ties. These generally comprise 6mm diameter deformed stainless steel bar, incorporating a neoprene drip. Other types of proprietary remedial tie can also be installed.
Left: Endoscope Survey / Right: Cavity Wall Tie Detector
Left: Stitch Drilling / Right: Brick Removal
Removal of Wall Tie
Typical examples of the two remedial wall ties in diagrammatic form are shown:
Once the agreed replacement wall tie has been installed, the corroded wall ties may be cut out and the brickwork and pointing made good. The surface is cosmetically finished to blend in with the surrounding surfaces. If required, the replacement ties can be random tested to ensure correct installation.
Any cracking resulting from the original wall ties defect can be repaired by Falcon using their epoxy resin bonding techniques (refer to Resin Bonding/Anchors Data Sheet).
Inner and outer leaves grouted with thixotropic resin
Stainless steel mechanical tie secured by torque action
Whatever your structural defects, please contact our local office for a competitive estimate on domestic, commercial or industrial projects.
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