Expansion joints should be located where stresses or cracks are likely to develop in brickwork.
Brick wall expansion joint.
Clay brickwork will generally be subjected to long term expansion while concrete masonry aggregate blocks aircrete blocks will be prone to shrinkage.
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 allowed movement helps prevent distortion and cracking.
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.
Exterior wall exterior wall expansion joints feature watertight.
This allows the joints to partially close as the brickwork expands.
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.
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.
Prime candidates for expansion joints include long expanses of walls corners offsets setbacks and parapets.
These joints will absorb the pressure created by the expansion by giving the masonry wall flexible space to expand.
The expansion and contraction of masonry needs to be accommodated and controlled by the inclusion of both vertical and horizontal joints within the building.
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Most general purpose bricks have a coefficient of expansion in the range 0 5 to 1 0mm m over 15 years.
This movement could be a result of thermal expansion moisture movement creep and structural loading or the effect of chemical changes.
Expansion joints should also be located below shelf angles to account for vertical expansion of brick.
An expansion joint in brickwork and blockwork is a means of solving potential problems caused by movement.