How to Manage Efflorescence in Brickwork: Causes, Prevention, and Treatment

Efflorescence refers to the appearance of white, chalky deposits on brickwork surfaces, a result of soluble salts, such as those from magnesium, calcium, potassium, or sodium, that dissolve in water. These salts may come from the clay used in brick production or the sand mixed into mortar.

Sources of Soluble Salts

• Clay: Bricks made from clay contain natural soluble salts that can lead to efflorescence and, in some cases, sulfate attacks on cement mortar.
• Mortar Sands: Sands, especially those from rivers or pits, generally contain minimal salts. Sea sands, however, require thorough washing before use.
• Cement: While Portland cement has limited impact on efflorescence, some modern cements with alternative binders may contain sodium sulfate.

How Efflorescence Forms

When water dissolves salts within bricks or mortar, it holds them in solution. As water evaporates, the solution concentrates, depositing salts on the surface or within the pores of the brick.

Minimizing Efflorescence Risks

While eliminating efflorescence entirely is challenging, limiting water penetration can reduce its occurrence. Key methods include:

• Design Considerations: Include overhangs, copings, and other details to direct runoff away from brick surfaces.
• Site Management: Site supervisors should protect bricks from moisture and contamination and shield new brickwork from rain.
• Brick Selection: Bricks can be tested for efflorescence levels before procurement.

Treating Efflorescence

To manage efflorescence, periodically brush off salt deposits with a bristle brush. Avoid using wire brushes or washing with water, as this re-dissolves the salts into the brickwork.

Conclusion

Efflorescence is a common issue in brickwork but can be managed through strategic design, construction practices, and maintenance. By understanding its causes and implementing preventative measures, you can enhance the appearance and longevity of brick structures.