Why Do Garden Walls Turn White?

Efflorescence is a problem that occurs on brick walls. It turns the wall white shortly after construction. Although this whiteness does not affect the structural integrity of the wall, it can be aesthetically unpleasing. There is no easy way to get rid of the ugly white stains.

Efflorescence

Efflorescence is a white powdery substance left behind by water-soluble salts as the moisture in the masonry begins to evaporate. Efflorescence usually appears shortly after the wall is built, but it can appear up to one year after construction.

Prevention

Efflorescence can only occur when there are water-soluble salts present in the masonry. Although there is no way to rid masonry of these salts, they can be greatly reduced. In addition to using an alkali reduced brick, care in construction can ensure that no excess moisture makes it into the bricks. When feasible, overhangs should be built to prevent moisture in the environment from entering the masonry while it is curing.

Removal

Depending on the type of salt, some efflorescence can be brushed away with a wire brush. The traditional method for tough stains is to use sandblasting. Sandblasting is an effective way to remove the white, but it may also damage the bricks beneath. If sandblasting is necessary, the masonry should be shielded with a waterproof solution to prevent water from re-entering the bricks.

Cure

Once efflorescence has started, it will not stop until the wall is completely free from moisture. The removal of efflorescence can lead to it returning heavier than before from water used in the removal process.