Mechanical Fixings

Cracks in Brickwork – How to minimise the risk.

Bed Joint Reinforcement

Brickwork is at its strongest in compression, however cracks in brickwork may become a factor once tensile forces are introduced. Reversible movement, irreversible movement and door and window openings induce tensile forces. Such forces may be modified or controlled by bed joint reinforcement, which can accommodate the tensile forces and help bond adjacent courses together in a uniform mass.

Tensile Forces

Tensile Forces

Mechanical Fixings in Brickwork – When are they required?

Additional support may be needed where innovative detailing is used. For example, where corbelling is detailed or where the bearing for successive courses is 103mm, brickwork less than 70mm may require proprietary channels. Cranked or special ties and angle supports fixed back to a reinforced concrete or concrete cased steel structure may also be required. The use of SBR (Styrene Butadiene Rubber) additive may be used where bricks need to be bedded on stainless steel angles. These additional supports help prevent cracks in brickwork.

Wall Ties – Why do I need them?

Wall ties

Wall ties

Non-Loadbearing arches, particularly those possessing a small rise in relation to their span, may similarly require additional support or restraint.

Arches in Brickwork

Arches in Brickwork

Wall Ties in traditional cavity brickwork

Cavity brickwork must incorporate wall ties (usually stainless steel) embedded in the horizontal mortar joints to a minimum depth of 50mm. Tie length and type depends upon the cavity width and requirements for strength, flexibility and retention of insulation materials. Wall Ties should be staggered and evenly distributed typically at 900mm centres horizontally and 450mm centres vertically.

Where else should Wall ties be used?

Additional ties should also be provided within 225mm of movement joints or openings at a maximum 300mm vertical centres.

For additional information with regards to joint movement, please see the, Movement of Brickwork Blog