What is Efflorescence ?

Efflorescence is the white salty deposit sometimes seen on bricks.

"Salts in brickwork are dissolved by water which is introduced during construction or from rain. As the wall begins to dry out, the solution of salts becomes more concentrated and the dissolved salts will be deposited on the surface of the brickwork. This tends to be more prevalent at low temperatures, i.e. early Spring"

What causes Efflorescence ?

For efflorescence to occur, three conditions MUST exist:

  1. There must be salts present somewhere in the wall, either in the bricks themselves or the cement
  2. There must be sufficient moisture present in the wall to solubilise the salts
  3. There must be a path for the soluble salts to migrate through, to the surface of the brick where the moisture can evaporate

If one of the above conditions doesn't exist then efflorescence cannot occur


Can Biostrip cause efflorescence ?

Biostrip is a water based technology and as such,  if conditions 1 and 3 are present then there is a potential for efflorescence to occur. The potential for this to happen can be reduced by carrying out stripping in late spring or summer when the weather is warmer. Efflorescence is more prevalent in colder weather.

It should be noted however that efflorescence is quite harmless. It can often be removed by brushing, although avoid a wire brush as this can damage the bricks or mortar. Some websites recommend use of a phosphoric acid based cleaner followed by a neutralisation stage using an alkaline detergent