BU593 Efflorescence (2016)

Efflorescence generally appears as a white deposit (although it may also be brown, green or yellow in colour) on the surface of clay and concrete masonry and concrete walls. Although efflorescence does not affect the performance of blockwork, brickwork or concrete, it is considered unsightly and spoils the appearance of the wall.

This bulletin describes how soluble and insoluble efflorescence can be identified and removed. It updates and replaces Bulletin 442 Efflorescence on masonry.

The bulletin covers:

• why does efflorescence occur
• efflorescence process
• controlling efflorescence
• removing soluble efflorescence
• removing insoluble efflorescence
• safety precautions.