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Last Updated: , Created: Thursday, September 14th, 2000

Peeling paint on a foundation wall.

Michele in Hamilton, Ontario needs to repaint her cinder block walls on the outside of the basement. But a close look at a photo that she sent us showed a lot of deep holes or pock marks in the blocks.

Not only the paint was peeling off, but the block itself was breaking off. 

This is a sign of a lot of water getting in behind the paint and freezing there.

First find the source of water. It could be water pooling near the wall and soaking upwards, or cracks or lack of flashing above, allowing rain water to move down. It could even be a very humid basement without a vapour barrier on the insulated wall. Stop the water source first.

Then scrape or sandblast off all of the existing paint as it is probably an oil paint that is trapping moisture inside the blocks.

Then repair the holes with a concrete patching compound like "Top-n-Bond".

Then paint with a "breathable" paint, a paint made for concrete.

Keywords: Moisture, Finishes, Foundation, Walls, Concrete, Repair, Blocks, Basement, Paint, Water

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