The short answer
Efflorescence is salt left on the surface when water moves through masonry and evaporates. Remove it with the gentlest method first, usually dry brushing, then water. It will keep coming back until the source of the moisture is found and fixed.
What it is and what it tells you
- White or gray powdery or crystalline deposits on brick, stone, block or concrete
- Water inside the masonry has dissolved salts and carried them to the surface
- Some is common in new masonry as it dries out
- Persistent or growing efflorescence on an older building means water is getting in somewhere
How to remove it
- Dry brush the deposits off first. Wetting them can drive salts back into the masonry.
- Rinse with water if dry brushing is not enough, and let the wall dry.
- Use a cleaner made for efflorescence only if needed, tested on a small area first. Acidic cleaners can damage masonry and mortar if misused.
- Protect glass, metal and landscaping from cleaner and runoff.
Why it keeps coming back
- Failed sealant joints or flashing
- Water from roofs, gutters or downspouts running down the wall
- Irrigation hitting the facade
- Moisture moving up from the ground
Fix the source, or plan to keep removing it. Clogged gutters are a common culprit. See the real cost of deferred exterior maintenance.
When to call in more help
Heavy, recurring efflorescence with cracking, spalling or interior moisture is a building envelope issue for a masonry contractor or engineer, not just a cleaning job.
S&K cleans brick and stone facades and clears gutters that send water down walls. Ask your local team to look at what you are seeing. See pressure and soft washing.
Not sure what you are looking at? Use the glass and metal damage triage guide, read the full Facade, Glass, and Metal Restoration guide, or have our team assess the surface and recommend the right approach, in writing.
