What is stucco?
Updated August 2026
Stucco is a cement-based plaster applied wet in layers over lath and cured into one hard, continuous shell around the house. The traditional mix of portland cement, sand, lime, and water goes on in three coats totaling about 7/8 inch over galvanized metal lath and two layers of building paper. It dominates the Southwest and California and turns up on older homes nationwide. Its lookalike, EIFS, is a different assembly altogether: foam board under an acrylic skin roughly 1/16 inch thick.
Where it is
Two checks tell you which one you own, and they take a minute. Knock on the wall with a knuckle: real cement plaster is rock hard and unforgiving, while EIFS sounds hollow and dents under thumb pressure. Then crouch at the base of the wall and hunt for the weep screed, a perforated metal edge that lets water inside the assembly drain back out. Code places it at least 4 inches above soil and 2 inches above paved surfaces. Stucco running straight down into a raised flower bed, or a base with no screed visible at all, sits behind a large share of hidden rot claims.
What it does
Stucco is not waterproof, and grasping that explains everything else about it. The wall absorbs rain, holds it briefly, and dries out, while the building paper behind it serves as the real drainage plane and the weep screed lets water leave. That is why hairline cracks under 1/16 inch, which every stucco house grows during curing and settlement, are cosmetic. What is not cosmetic: cracks over 1/8 inch, diagonal cracks radiating from window and door corners, bulges, soft spots, and rust-colored streaking, all of which say water is sitting behind the lath, corroding it and wetting framing. Barrier EIFS installed before the mid-1990s had no drainage path whatsoever and rotted sheathing behind it, which is why inspectors and lenders still ask. The cement version itself lasts 50 to 80 years, and its failures gather at the edges, the penetrations, and the base.
Maintenance
Twice a year, walk the walls and study the transitions rather than the open field: window and door perimeters, hose bibs, vents, and the line where stucco meets trim or roof. Seal any crack wider than a business card edge with a compatible elastomeric patch, recaulk penetrations every 5 to 10 years, and keep soil and mulch below the weep screed. Aim sprinklers away from the wall, because a head soaking the same 3 feet of stucco every morning is a slow-motion leak. Recoating intervals live in how often to reseal stucco, the full routine in the stucco checklist, and the aging curve in how long stucco lasts.
What it costs to replace
A replacement stucco finish runs $8–20 per square foot to patch and re-texture a damaged section, $7–12 per square foot to re-stucco down to the lath, and $2–5 per square foot for an elastomeric recoat over sound walls.
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Frequently asked questions
Are cracks in stucco normal?
Hairline cracks under 1/16 inch, about the width of a business card edge, are normal and show up on nearly every stucco house as the cement cures and the frame settles. Seal them at the next recoat and move on. Cracks wider than 1/8 inch, cracks running diagonally from a window or door corner, cracks with staining beneath them, and any area that sounds hollow or feels soft belong in a different category: those are water or movement, and they deserve a look before the next rainy season.
How can I tell stucco from EIFS, and why does it matter?
Press hard with a thumb. EIFS gives, because foam sits behind it; cement stucco does not move at all, and a magnet finds the metal lath underneath. The distinction matters at three moments: insurers and lenders sometimes treat pre-1996 barrier EIFS as a risk, repairs use completely different materials, and pre-purchase moisture testing costs $400–800 on an EIFS house for good reason. Modern drainable EIFS performs well, so age and detailing matter more than the label.
What does staining below a window on stucco mean?
Water is getting behind the wall and finding its way back out. The usual suspects are failed caulk at the window perimeter, missing or damaged head flashing above the opening, and a sill that was never sloped to drain. Rust-colored streaks mean the lath or the fasteners are corroding, which is further along. Have it opened up rather than painted over: a $400–900 flashing and patch repair now beats replacing rotted sheathing later. Repair or replace stucco walks the threshold.
Can you paint or seal stucco?
Yes, with a breathable coating. Acrylic masonry paint or an elastomeric coating at $2–5 per square foot bridges hairline cracks and typically holds 7 to 10 years. Skip oil-based paint and film-forming waterproofers, because stucco has to dry outward and a sealed face traps moisture in the wall and blisters off. Integral-color stucco needs no paint at all, only washing and crack repair. Whatever goes on, clean the wall first and let fresh patches cure 28 days.