I have a garage built with concrete blocks and the walls are surrounded on the outside by a layer of concrete rendering.

The problem is that large cracks have built up in the rendering over time, probably as there are no expansion joints anywhere.

I'm considering what might happen in the winter if water/ice gets into/behind these cracks and starts to make some of the rendering fall off.

I was going to paint over the cracks, however is there a better way than this that I can preserve the current state of the rendering?

(P.S.: I'll post some pictures if it helps)

Update: pictures now added:

Close up enter image description here

  • 3
    Yes pictures would help understand how the cracks are situated. I had to Google rendering, I never heard the term before. It appears to be another term for stucco.
    – Jack
    Apr 9, 2014 at 11:27
  • You do want to prevent water entry. Caulk any cracks big enough to accept caulk. Any smaller (i.e. "hairline") cracks should be able to be bridged with latex paint alone. If there's any gaps too big to caulk fill them with more rendering.
    – bcworkz
    Apr 9, 2014 at 17:30

1 Answer 1


There are stucco crack patch products out there. For lack of a better explanation, they are essentially sanded caulk:

enter image description here

Use that to fill in the cracks, then paint over with proper stucco paint (breathable latex).

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