I understand all foundations develop vertical, cosmetic cracks over time. My question is how many is too much and cause for concern? It’s a poured concrete foundation and was completed less than two years ago. I’ve noticed 4 hairline cracks by window a few months after completion. Now I’m noticing more with some starting at the very top running vertical all the way down to the bottom. Should I be concerned?
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Replies
No, hairline cracks are to be expected. If the cracks start to open up or you notice what seems like a lot of new cracks developing may need to be concerned. Concrete cracks, just the way it goes. If your foundation has been installed with proper waterproofing you have no issue with leaks. The waterproofing will span and stretch over the hairline cracks.
Thank you for your reply. What started off with 4 cracks is now up to 8 when I did a walkthrough in my basement.
I wouldn’t worry too much about it yet. You will notice most of the settling of a new home happens in the first couple years. 8 hairline cracks for the whole basement isn’t bad at all. Those hairline cracks often occur in areas where metal reinforcing and anchor bolts are located. Don’t really know why, maybe b/c the steel creates a void in the concrete which makes it more likely to crack. There are structural cracks and cosmetic cracks, yours sound cosmetic. If overly concerned give your builder or the foundation company a call. If the cracks get to 1/8” wide or you see leaking probably best to have someone take a look.
Cracks occur because the concrete shrinks. Coupla reasons for this, but mostly concrete moves from changes in temperature. If it's restrained, say around a steel beam or column, it cracks there. If there's a differential in the height of a wall, say at a window, there's a weak point at the corner and cracks occur there. Like they say - There are two types of concrete. One that's cracked and the other that hasn't cracked yet.