Important Notice: Our web hosting provider recently started charging us for additional visits, which was unexpected. In response, we're seeking donations. Depending on the situation, we may explore different monetization options for our Community and Expert Contributors. It's crucial to provide more returns for their expertise and offer more Expert Validated Answers or AI Validated Answers. Learn more about our hosting issue here.

What causes white powdery deposits on masonry surfaces, and how can I fix them?

April 26, 2017causes deposits Fix masonry powdery surfaces white

0

Posted

What causes white powdery deposits on masonry surfaces, and how can I fix them?

1 Answer

0

Posted

The deposits, known as efflorescence, are caused by moisture in the masonry. The moisture dissolves salts in the masonry — the mortar, block, concrete, etc. — and is drawn to the surface by the heat of the sun. The water evaporates, leaving behind white deposits that must be removed before painting. After you find and fix the source of the moisture, remove the efflorescence with a wire brush and coat the surface with a masonry primer and topcoat.