What is that white stuff on my stone?

How to remove efflorescence from natural stone and brick.

Stonedoctors are often asked for advice on how to remove white residue from the natural stone or brick. The white residue is in fact is called efflorescence, or in other words the natural salts and minerals found in natural stone and brick.

This is a very common problem.

What happens is that natural salts in the material are carried to the surface and deposited by water penetrating into the material and moving through the microscopic pores in the brick / stone. Once the water evaporates from the surface the salts are left and the sun then solidifies the salt deposit on the surface of the material.

The ideal time to deal with this and remove the salt residue is before it hardens on the surface using a non acidic efflorescence cleaner like our Skavenja Cleaner.

However more often that not the salts have hardened and an acidic cleaner is needed like our Stontex Cement Away to break down the salt deposit and remove it from the surface. However some materials are acidic sensitive i.e. limestone, marble and concrete that can etch / discolour the material so you need to keep this in mind, but you have little choice unless you engage a specialist that can remove with a special machine without the use of chemicals (this can be quite expensive and we have recommended specialists that can carry out this work if someone wishes to go down this route).

If you are not sure how your stone or brick reacts to acidic cleaners the best approach is to test a small area first. If you are happy with the results you then can apply the product to the rest of the area.

Here are ‘before’ and ‘after’ pictures of a red brick wall with efflorescence that has been cleaned with Stontex Cement Away and sealed with Dry Treat Stain Proof (2 coats) to  help prevent the re-occurrence of white staining in the future.