Efflorescence, a cosmetic problem or a structural threat?

Efflorescence, a cosmetic problem or a structural threat?

Ever wondered what that white powder is on your brickwork? This blog looks at what efflorescence is and whether it poses a structural threat.

What is efflorescence?

Efflorescence is a fine, white, powdery deposit of water-soluble salts left on the surface of masonry as the water evaporates.

Three conditions must exist before efflorescence can occur:

  • First: There must be water-soluble salts present somewhere in the wall.
  • Second: There must be sufficient moisture in the masonry product to render the salts into a soluble solution.
  • Third: There must be a path for the soluble salts to migrate through to the surface where the moisture can evaporate, thus depositing the salts, which then crystallize, and cause efflorescence.


Can efflorescence damage my home?

Generally efflorescence is a cosmetic problem. However, as stated above, there must be sufficient moisture content in a masonry product for efflorescence to take effect. Excessive moisture can contribute to many structural issues, such as rising damp or mould growth, & can even cause concrete cancer & foundation movement. If you are concerned that your home may be subject to moisture damage, it is always best to contact a suitably qualified inspector.

How do I remove efflorescence?

  • Firstly it should be noted that often the removal of efflorescence could be a laborious & ultimately unsuccessful task. The following methods may be recommended for removal of efflorescence:
  • Get the wall bone dry (where possible), and then try to remove the powder with a stiff brush. Lift off any remaining crystals with a damp sponge. This method is our recommendation for removal.
  • Water blasting & hosing may initially look good, although ultimately you have just added moisture to the problem & during the drying process the problem may increase.
  • Acids often state that they will clean off efflorescence although the efflorescence must be washed down before application, & as above the results may initially seem successful but you may have just restarted the cycle. We believe the inconvenience & danger to the user outweighs the likelihood of a successful outcome.
  • Alkaline cleaners could also possibly work although research suggests that the alkali content in Portland cement is a key contributed towards efflorescence, & as such there is a real possibility that you could be putting more salts into the wall.

Efflorescence will often be described as a ‘passing nuisance’, although as explained it indicates a potential moisture problem. If located in an area of little importance when exposed to moisture then efflorescence should be seen for what it is, a sign of life from a product made of natural, raw materials.

Author: Lewis Flatt – Cap-It-All Building Inspections, Servicing the Perth Metro Area

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