UnderCover: Waterproofing and Underpinning Secrets: Episode 27 💧 The Truth About Efflorescence in GTA Basements

That chalky white powder spreading across your basement wall may look like mould or damaged concrete, but it is often something called efflorescence.

In Episode 27 of UnderCover, the DGI Waterproofing team explains what efflorescence is, why it appears on concrete and block walls, and what it may be telling you about moisture around your foundation.

Efflorescence forms when water moves through masonry, dissolves natural mineral salts, and carries them to the wall’s surface. Once the water evaporates, a white or greyish deposit remains. The deposit itself is usually harmless, but the moisture behind it may need attention.

Key Topics Covered:

• Why Efflorescence Forms: Learn how moisture travels through basement walls, carries mineral salts to the surface, and leaves behind a chalky white deposit.
• Efflorescence or Mould: Understand the differences between dry, gritty mineral deposits and mould that may look soft, fuzzy, discoloured, or smell musty.
• Signs of an Active Moisture Problem: Find out why recurring deposits, damp walls, peeling paint, dark stains, or nearby mould may mean water is still entering the foundation.
• Cleaning, Monitoring, and Waterproofing: Discover how to safely brush away deposits, track changes with dated photos, and recognize when professional help may be needed.

We also discuss why GTA homes may be more likely to experience basement moisture because of clay soil, heavy rain, melting snow, poor grading, short downspouts, clogged gutters, and freeze-thaw cycles.

A small deposit that brushes away and does not return may only need monitoring. When the powder keeps coming back, the wall feels damp, or a musty smell develops, it is worth finding the source instead of simply covering the area with paint.

For homeowners dealing with recurring wall moisture, DGI Waterproofing provides basement waterproofing solutions for damp foundations and ongoing efflorescence problems across Toronto and the GTA.

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