What should I expect to pay for removing efflorescence and re-sealing a brick foundation wall?

For a typical GTA home, expect to pay between $500 and $2,500 to have efflorescence professionally removed from a brick foundation wall and a penetrating sealer applied, depending on the total area, severity of the salt deposits, and accessibility of the wall. A small section (under 50 square feet) with light efflorescence runs $500–$800, while a full perimeter treatment on a larger home with heavy buildup can reach $2,000–$2,500.

Efflorescence — those white, powdery or crystalline mineral deposits on brick and mortar — is caused by water migrating through the masonry, dissolving soluble salts in the brick, mortar, or concrete, and depositing them on the surface as the water evaporates. In the GTA, this is an extremely common issue because of our clay soils that hold moisture against foundation walls, road salt splash from driveways and sidewalks during winter, and the sheer volume of moisture cycling through masonry during 50+ annual freeze-thaw cycles. Homes in Scarborough, North York, Mississauga, and Brampton — areas with heavy clay soil — are particularly prone to persistent efflorescence.

The removal process itself involves scrubbing the affected areas with a stiff masonry brush and a commercial efflorescence remover (typically a diluted acid-based solution). For heavy or recurring efflorescence, contractors may use a pressure washer at low pressure (under 1,500 PSI to avoid damaging mortar joints) followed by a chemical treatment. The wall must then dry completely — typically 48–72 hours of dry weather — before any sealer is applied. A penetrating concrete and masonry sealer (silane or siloxane-based) is then brushed or rolled onto the brick, soaking into the pores without changing the appearance of the masonry. This sealer repels water at the surface level, dramatically reducing the moisture migration that causes efflorescence in the first place. GTA pricing for the sealer application alone runs $3–$7 per square foot.

The critical thing to understand is that efflorescence is a symptom, not the disease. If water is reaching your foundation wall because of poor grading, clogged or disconnected downspouts, failed weeping tile, or deteriorated mortar joints, sealing the surface will slow efflorescence but won't eliminate it permanently. Before spending money on cleaning and sealing, check that the soil grades away from the foundation (a minimum 6-inch drop over the first 6 feet), downspouts extend at least 6 feet from the wall, and window wells have functioning covers and drains. Fixing drainage is often the cheapest and most effective step — and something most homeowners can handle themselves.

For a DIY approach on a small area, you can purchase efflorescence remover ($15–$30 per litre at any GTA building supply store) and a penetrating masonry sealer ($80–$150 per pail, covering approximately 200–400 square feet). Clean the surface with the remover using a stiff brush, rinse thoroughly, let it dry for 2–3 days, and apply the sealer with a roller or brush. This is a reasonable weekend project for light efflorescence on accessible walls. However, if the efflorescence is heavy, recurring, or covers large areas, a professional assessment is worthwhile because persistent efflorescence often signals moisture issues behind the wall that need investigation — and those issues, left unchecked, lead to mortar deterioration, brick spalling, and eventually structural concerns. A qualified mason can also check mortar joints during the cleaning process and recommend tuckpointing where needed, which runs $8–$25 per square foot in the GTA market.