Foundation cracks on the Wasatch Front are a different conversation from foundation cracks in most of the country. The reason is the soils — much of Davis and Weber counties sit on clay-heavy deposits that swell with moisture and shrink when they dry. That seasonal cycle, repeated over decades, produces a pattern of basement wall cracking that's specific enough to recognize. Most of it is cosmetic. Some of it isn't. Knowing the difference is the entire job.
The four crack types you'll see
1. Vertical hairline cracks
These are by far the most common. A vertical line, usually less than 1/16 inch wide, often near a corner or below a window. Almost always cosmetic. Vertical hairline cracks are usually shrinkage from when the concrete was originally poured — concrete shrinks slightly as it cures, and the wall has to crack somewhere. They're stable, they don't grow, and they don't mean anything is wrong with the structure. You can fill them with epoxy if you want, but they don't need engineered repair.
2. Diagonal or stair-step cracks in block walls
Step pattern in masonry or block walls, usually starting at a corner and moving up at 45°. Sometimes cosmetic, sometimes a sign of differential settlement or expansive clay pressure. The key questions: are they growing, and is the wall moving inward? Mark the ends and watch for 6 months. If they're stable, they're old movement that has stopped. If they're active, an engineer should look.
3. Horizontal cracks across a basement wall
A horizontal line running parallel to the floor, typically a few feet up from the bottom of the wall. This one is often serious. Horizontal cracks in a basement wall usually mean the wall is being pushed inward by lateral pressure from the soil — exactly the kind of pressure expansive clay generates as it swells. Combined with any visible inward bowing of the wall, it means the wall is actively distressed and needs evaluation. We see this most often in 1960s and 1970s Davis County basements with thinner-than-modern walls.
4. Wide cracks (over 1/4 inch) anywhere
Width matters. A crack you can fit a coin into is a different problem from a hairline. Wide cracks suggest meaningful differential movement and are worth a real evaluation, even if the orientation looks otherwise harmless.
Why expansive clay does this
Expansive clay soils contain mineral structures that absorb water and physically swell. When the soil dries, they contract. That swell-shrink cycle, repeated through Utah's wet winters and dry summers for decades, applies pressure against any wall the soil is in contact with. Foundation walls absorb that pressure. Modern walls are designed for it. Older walls (especially pre-1980 8-inch walls) often weren't, which is why you see more horizontal cracking and bowing in older Davis and Weber County basements.
The other thing expansive clay does is move differentially. One corner of the soil under your house gets wetter than another (because of a downspout, a sprinkler line, or a slope), and that part of the foundation moves slightly while the rest stays put. Over time you get small differential settlements that show up as stair-step cracks at corners.
What we'd actually do if you called us
- Look at the photos you sent. About a third of the time we can tell from the photos that the cracks are cosmetic and you don't need a visit. We say so. We don't charge.
- If the photos are inconclusive, schedule a visit ($350-$500 flat fee).
- On site, measure crack widths, document orientations, check for inward bowing of basement walls, look at exterior drainage and grading, and check the floor for any sloping.
- Write a short, honest report: cosmetic, monitor, or repair — and if repair, what kind and roughly what it would cost.
- If repair is needed, we can design the repair and stamp the plans. If not, we tell you to enjoy your house.
The DIY monitoring trick
If you're not ready to call an engineer but you want to know whether a crack is active, do this: take a clear photo with a tape measure or coin in frame, mark the very end of the crack with a pencil and a small note of the date. Check back in 6 months. If the pencil mark is still at the end of the crack, it's stable. If the crack has grown past the mark, it's active and worth a real evaluation.
See our foundations and retaining walls page for more on what we do, or just send us photos. We answer fast and we don't sell repairs.