Efflorescence, also known as “white bloom,” is a common problem on smooth concrete surfaces. It is caused by the migration of water-soluble salts to the surface of the concrete, where they crystallize and form a white, powdery residue. To remove efflorescence from smooth concrete surfaces, you can use the following steps:
- Brush the surface: Use a stiff-bristled brush to scrub the surface of the concrete, paying special attention to the areas affected by efflorescence. This will help to loosen the crystals and remove some of the surface buildup.
- Apply a cleaning solution: Mix a solution of equal parts water and white vinegar, or use a commercial efflorescence cleaner according to the manufacturer’s instructions. Keep in mind that some efflorescence cleaners can cause noticeable etching if improperly applied.
- Scrub the surface again: Use the stiff-bristled brush to scrub the surface again, working the solution into the concrete and removing as much of the efflorescence as possible.
- Rinse the surface: Rinse the surface thoroughly with water to remove any remaining cleaning solution and efflorescence.
- Repeat as necessary: Repeat the process if needed, until the efflorescence is removed.
- Preventative measures: You can help prevent future efflorescence by applying a permanent deep penetrating concrete sealer (DPS) such as Dynacrete PIM+ or PIM+ Type S that will inhibit water vapour transmission and reduce the possibility for the salt to migrate to the surface or apply a water/acrylic based glossy top sealer which should be reapplied every 2 years.
It’s important to note that efflorescence can reoccur after cleaning because of the salts that are still in the concrete, so it’s important to take preventative measures on newly poured concrete to inhibit the possibility of occurrence or reoccurrence of an efflorescence blossom.