1 3mm per linear run of brickwork should be allowed so a wall that has movement joints at 9m centres should have a joint of 12mm.
Brick wall expansion joint.
This allowed movement helps prevent distortion and cracking.
Exterior wall exterior wall expansion joints feature watertight.
An expansion joint in brickwork and blockwork is a means of solving potential problems caused by movement.
Prime candidates for expansion joints include long expanses of walls corners offsets setbacks and parapets.
Expansion control joints to control the expansion and protect the wall structure from cracking under pressure masons install vertical control joints at specific locations.
This allows the joints to partially close as the brickwork expands.
The joints are formed by leaving a continuous unobstructed opening through the brick wythe that may be filled with a highly compressible material.
Expansion joints should be located where stresses or cracks are likely to develop in brickwork.
Clay brickwork will generally be subjected to long term expansion while concrete masonry aggregate blocks aircrete blocks will be prone to shrinkage.
They are therefore specifically provided in boundary walls to avoid cracks occurring in the wall.
The coefficient of expansion or e value of clay bricks when tested in accordance with as nzs 4456 11 can vary from a very low 0 3mm m millimetres per metre to over 1 6mm m.
This movement could be a result of thermal expansion moisture movement creep and structural loading or the effect of chemical changes.
These joints will absorb the pressure created by the expansion by giving the masonry wall flexible space to expand.
Most general purpose bricks have a coefficient of expansion in the range 0 5 to 1 0mm m over 15 years.
Expansion joints must be located so that the structural integrity of the brickwork is not compromised.
A masonry expansion joint is a complete break in the masonry wall to allow for the entire structure to move under loading temperature related expansion contraction etc.
Brickwork showing wall ties spaced no more than 225mm from the expansion joint movements joints and their size vary depending on the size of the wall.
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