Brick Wall Expansion Joint
An expansion joint in brickwork and blockwork is a means of solving potential problems caused by movement.
Brick wall expansion joint. When building a boundary wall an expansion joint is a separation designed to relieve stress on building materials caused by movement induced by thermal expansion and contraction. 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. Exterior wall exterior wall expansion joints feature watertight.
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. The joints are formed by leaving a continuous unobstructed opening through the brick wythe that may be filled with a highly compressible material. They are therefore specifically provided in boundary walls to avoid cracks occurring in the wall. Expansion joints must be located so that the structural integrity of the brickwork is not compromised.
Expansion joints should be located where stresses or cracks are likely to develop in brickwork. This movement could be a result of thermal expansion moisture movement creep and structural loading or the effect of chemical changes. 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. Clay brickwork will generally be subjected to long term expansion while concrete masonry aggregate blocks aircrete blocks will be prone to shrinkage. This allows the joints to partially close as the brickwork expands. Exterior vertical wall expansion joint selection guide emseal watertight fire rated sound proof insulating precompressed foam sealant expansion joints selection guide.
Expansion joints should also be located below shelf angles to account for vertical expansion of brick. 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.