Reading Foundation Cracks

Reading Foundation Cracks

As concrete cures, it shrinks slightly. Where the concrete can’t shrink evenly, it tends to crack. Concrete and block foundations usually have at least a few cracks. The trick is recognizing which are insignificant and which are serious. Here’s a list from least to most serious:

Hairline cracks in the mortar between concrete blocks are rarely worth worrying about.

Cracks at an L-shape section, such as where a foundation steps down to follow a hillside, are probably shrinkage cracks, especially if they meander and taper down to a hairline. These aren’t a structural issue, though you might need to plug them to keep the basement or crawl space dry.

Stair-step cracks in masonry joints are a bigger concern, especially if the wall is bulging or the crack is wider than ¼ inch. A plugged gutter or other moisture problem outside is probably exerting pressure on that part of the wall.

Horizontal cracks are most serious. It may be that water-saturated soil froze and expanded, pushing in and breaking the foundation. Or, you may have soil that expands when damp and shrinks when dry. You may have a serious foundation problem. Call Foundation Technologies for a no cost evaluation and repair estimate.

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