What is Efflorescence?

In French ‘efflorescence’ means to flower out and is the migration of salt to the surface of a porous material, where it forms a coating.

It often occurs in masonry construction, particularly in mortar and bedding compounds of brick or external tiles when moisture/water is driven out of the building material as a result of the climatic changes such as heat hydration which brings salts to the surface (originally contained in the mortar mixes of sand and lime). As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit, that can normally be brushed off. The resulting white deposits are referred to as "efflorescence" in this instance.

Efflorescence, it is not a structural, but rather an aesthetic building concern.

Efflorescence and water-proofing failure are common problems in the construction industry. Concrete materials such as tile beds, adhesives, grout, concrete and render are all ordinarily porous. Water absorption allows free lime to be dissolved and be transferred to an exit point where it forms unsightly deposits of calcium carbonate. In wet area tiling, this same porosity means water proofing membranes have to work hard with perpetual saturation.

Is Efflorescence considered a building defect?

The answer is, Yes. Section 13.08 from The Guide to Standards & Tolerances 2015 states;

“Calcification and efflorescence associated with decks and balconies

Calcification or efflorescence caused by water coming from a deck or balcony that occurs

on walls below or beside the deck or balcony, or that appears in the mortar joints of the

deck or balcony tiling, is defective. Activities of others, such as owners watering plants, may

also contribute to the efflorescence, which may not be attributed to the work of the builder.”

Protecting against Efflorescence

Adding a chemical agent such as ‘Efflock’ to the building material during construction will protect against efflorescence but this additional protection effort is rarely done by builders or contractors.

 It is also possible to protect porous building materials, such as brick, tiles, concrete and paving against efflorescence by treating the material with an impregnating, hydro-phobic sealer. This is a sealer that repels water and will penetrate deeply enough into the material to keep water and dissolved salts well away from the surface.

Removing Efflorescence

Crommelin Solutions manufacture a chemical compound known simply as ‘Efflorescence Remover’ which is an acidic cleaner used to break down the salt deposits and can also act as a durable cleaning prepping agent prior to sealing the area with a masonry or stone sealer. This product is available at leading hardware stores.

 In extreme cases light sand blasting to masonry brickwork may be required by a professional contractor.