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Efflorescence Removal



Efflorescence is the term most commonly used to describe the deposit of crusty white mineral salts that appear on a masonry surface (concrete, render, brick or mortar) that has leached out from within the substrate when moisture migrates through it.

Efflorescence can happen at different times. Essentially, it can either be a problem from the beginning of a building’s construction, or the process can occur over time. Primary efflorescence usually occurs within the first 72 hours of the building material being used, appearing due to excess water being present when the material is manufactured. Secondary efflorescence is a result of outside moisture pulling the salt out of the building material at PH Exterior Cleaning Services we use the appropriate mix of strong industrial chemicals to remove stubborn efflorescence. The exact approach will be discussed and agreed at the time of site survey


Efflorescence is caused by water-soluble salts and other water-dispersible materials that come to the surface of concrete, bricks and mortars on both internal and external walls. 

There are a number of potential causes, including:

  •   Low temperatures.

  • Moist conditions.

  •  Condensation.

  • Rain 

  • Water added to the surface of fresh concrete to aid the troweling process.

  • Groundwater.

  • Three conditions must exist for efflorescence to occur:        

  • Water-soluble salts must be present.

  • Moisture must be available to transform salts into a soluble solution.

  • Salts must be able to move through a material to its surface. The moisture will then evaporate and cause the salts to crystallize, resulting in efflorescence.

Water moves and migrates through capillaries in  masonry, brickwork or mortar carrying salts to the surface. The fewer capillaries there are, or the higher the density of the material, the more difficulty the water will have in passing through to the surface. The higher the porosity of the material, the greater the likelihood of efflorescence occurring. As salt deposits are left behind by the evaporation of water, humidity levels influence the appearance of efflorescence.Low humidity can result in the evaporation of water prior to reaching the structure's surface, which means that the salt deposit remains unseen. High humidity can result in slower evaporation and hence more opportunity for growth of the deposits, therefore, contacting a professional contractor will help minimise the humidity inside the capillaries by sealing the surface.


Steps can be taken to prevent or limit the spread of efflorescence.

For example, in their natural state sand and gravel may have been associated with salt-bearing water or soil. This can lead to efflorescence unless the salts are removed by washing.
Mixing-water used for mortar or concrete may be taken from a natural source which has been in contact with a sulphate-bearing soil. In this instance, efflorescence can be reduced by using a low water-cement ratio mix for concreting.

Clay products such as building bricks and face bricks may also contain soluble salts.

To prevent or reduce this, the clay can be washed during the manufacturing process, and a barium salt. In terms of site storage, bricks should be kept off the ground in a dry place so as to prevent dampness or the absorption of moisture.


Contact now!

If you live in Northampton and surrounding areas and would like a FREE quotation and survey for EFFLORESCENCE cleaning, please make an online enquiry.

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