Typical defects that may trigger cracks include any one or a combination of:

• Ground movement – Subsidence, land slip or heave
• Inadequate support – Localised foundation failure, lintel failure, masonry arch failure, etc.
• Insufficient restraint – Lack of wall ties, restraint straps, poor bonding, etc.
• Resizing – Expansion or shrinkage due to thermal or moisture variations
• Rusting metals – Wall tie corrosion, expansion of hoop irons or fixings, etc.

Identifying and eliminating the cause of the fracturing is essential in ensuring the lasting success of a masonry repair scheme.

Generally crack repair strategies fall into one of two categories:

• Sub-structure repairs for below ground foundation movement issues, typically an insured risk
• Superstructure reinforcement for above ground building defects, typically an uninsured risk

Sub-structure repairs may include underpinning or piling.

Superstructure reinforcement generally includes structural repairs accomplished by the insertion of helical bars that form retrofitted brick beams or crack stitching systems Replacement wall ties and restraints tie cavity walls or separating façades,  whilst resin injection products efficiently fill and seal cracks in walls

After resolving the source of faults or weakness, fill the cracks and reinforce the zone of brickwork that has fractured to ensure once again it performs like an integrated structural unit. Crack repair techniques include mechanical brick stitching and crack injection resins, whilst various tie and strapping systems help to constrain further movement by transferring and sharing loads.