Home > Prevent damage to ceramic tiles and stone pavers from efflorescence with testing from Safe Environments

Prevent damage to ceramic tiles and stone pavers from efflorescence with testing from Safe Environments

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article image Efflorescence damage to stone pavers

Safe Environments  conduct efflorescence testing to Australian and New Zealand standards on masonry materials and stone pavers to measure their propensity to migrate salt laden solution and form efflorescence at the surface.

Efflorescence is the formation of insoluble salts that appear as white coloured staining on concrete, tiles, stone, and brickwork and is considered a building defect. There are two main types of efflorescence:

  • primary efflorescence due to the hydration process during the setting of cement
  • secondary efflorescence due to free water of a cementitous material allowing soluble salts to migrate to the surface, with the free water evaporating forming insoluble salts (efflorescence).
Ceramic tiles, stone and pavers are generally laid on concrete or leveling screeds that are of a cementitous material which include the constituents of efflorescence. These cementitous products are an abundant source of calcium hydroxide which is formed during the cement hydration process. The presence of free water, such as rain, may penetrate through the grout lines or into the masonry materials, which may then dissolve the calcium hydroxide.

If this salt water is then allowed to evaporate over time, the soluble calcium hydroxide may react with the carbon dioxide (CO2) in the air, forming an insoluble calcium carbonate (CaCO3) that forms the efflorescence. It is at these places of evaporation that high levels of the white coloured efflorescence are observed.

Masonary materials and stone pavers may be tested to determine their propensity to form efflorescence. The pavers and stone are partially submersed into a salt solution and observed over time to assess any development of efflorescence and the extent to which it forms. Safe Environments conduct efflorescence testing to AS/NZS 4456.6.

Primary efflorescence may not be able to be completely eradicated, however cleaning should remove the majority of initial efflorescence.

Secondary efflorescence, however, can be prevented by sound design practice and construction techniques which include:

  • minimising water penetration into the ceramic tile, stone or paver system for the calcium hydroxide to dissolve
  • ensuring adequate substrate drainage to prevent salt laden water from evaporating.

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