Almost every stucco house in Southern California has cracks. Most are harmless. A few are the only warning you'll get before a much more expensive repair. Knowing the difference saves homeowners thousands.
Hairline cracks — thin, shallow, spread across a wall — are usually shrinkage from curing or normal thermal movement. Stucco expands and contracts with our temperature swings, and hairlines are how it relieves that stress. They're cosmetic. A fog coat or elastomeric repaint handles them.
Diagonal cracks running off the corners of windows and doors are also common. Openings concentrate stress, and the corners are where it shows. On their own they're not alarming, but if they're wide enough to slide a coin into, water is getting behind the stucco and the paper and lath underneath need to be checked.
Stair-step cracks following the mortar joints of a block or brick wall are different. Those indicate movement in the structure itself — settlement, soil movement, or a failing footing. Patching the surface without addressing the cause is money thrown away; the crack comes back in the same place within a year.
Bulging, soft, or blown-out stucco is the urgent one. It means water has been getting in long enough to rot the framing or corrode the lath behind it. By the time stucco is falling off in sheets, the repair is no longer a stucco repair — it's framing, paper, lath, and stucco.
Good stucco repair always starts behind the surface: find the water, fix the paper and lath, rebuild the coats, then match the texture and color so the patch disappears. Skipping straight to the finish coat is why so many patches stand out like a scar.
Not sure what your cracks mean? Call ACA General Construction at (818) 326-5592 — we'll look at it and tell you honestly whether it needs repair now or can wait.