Stucco is a hard, cement-based finish sitting on a house that moves a little with the seasons. So nearly every stucco wall develops some cracking over time. That does not mean every crack is a problem — but some of them are, and the difference matters more in Northern Colorado than in milder climates.
Fine hairline cracks, thinner than a credit card and not growing, are usually cosmetic. They often show up in the first year or two as the stucco cures and the house settles, and they tend to run randomly across the surface. They are still worth keeping an eye on and sealing when the wall is next painted or re-coated, because even a small crack can let a little water in.
The cracks that deserve attention are the ones that are wider, growing, or telling you something about the structure behind them. Look for cracks you can fit a coin edge into, cracks that run diagonally from the corners of windows and doors, stair-step patterns, long horizontal cracks, and any area where the stucco bulges, sounds hollow when tapped, or feels soft.
Staining is another warning sign. Dark streaks running down from a crack, or discoloration below a window, usually mean water is getting behind the finish and coming back out. Inside the house, peeling paint or damp patches on the wall behind can point to the same thing.
This is where Colorado's weather makes things worse. Water that gets into a crack freezes overnight, expands, and opens the crack a little further. Then it thaws, more water gets in, and the cycle repeats dozens of times each winter. A crack that was minor in October can be noticeably bigger by spring.
The fix depends on the cause. Smearing caulk over a crack might hide it for a season, but if water is already behind the stucco, or the crack keeps moving, it will come back. A proper repair means finding out why the crack formed, cutting out any damaged material, rebuilding the layers underneath, and blending a new finish into the surrounding wall.
If you are not sure what you are looking at, that is exactly what an estimate is for. Call M&S Stucco & Stone at (970) 581-4342 and we will look at the wall with you and tell you honestly whether it needs work.