Casa Grande Stucco Repair Hollow, blistered, or falling stucco: delamination and what it costs to fix
Stucco that sounds hollow, bubbles outward, or comes away in sheets has delaminated: separated from the lath and paper behind it. That is a water problem that has already been going on for a while, and it cannot be coated over.
How to check it yourself
Tap the wall with a knuckle, working across the area and outward from any visible damage.
Solid and dull means the stucco is bonded. Drummy or hollow means it is not.
Map the hollow area with tape or chalk as you go. Almost always it extends well beyond anything visible, because water spreads behind the stucco before the surface fails. That mapping exercise is the single most useful thing you can do before calling anyone, and it takes ten minutes.
Then look for the source above it. Water got in somewhere, and it was almost certainly higher up.
Where the water came from
| Delamination location | Usual source |
|---|---|
| Below a parapet | Failed parapet top or cap |
| Below a canale | Canale flashing, or decades of discharge running down the wall |
| Under a window | Window flashing, or a failed sill detail |
| At the base of a wall | Splash-back, grade too high against the stucco, or irrigation |
| Around a light, vent, or penetration | Failed sealant at the penetration |
| Below a roofline or a scupper | Flashing at the transition |
| Randomly in a field of wall | Often a crack that has been taking water for years |
Fixing the delamination without fixing the source means doing it twice. Any quote that does not mention the source has not looked properly.
Why coating over it fails
This is worth being blunt about, because it is the most common bad repair in this trade.
A coating, elastomeric or otherwise, bonds to what is underneath it. If what is underneath is already separated from the wall, the coating bonds to a piece of stucco that is on its way off. The result looks fine for a season and then comes off in a larger sheet than before, taking your money with it.
If anyone proposes coating a wall without sounding it first, ask them to tap it in front of you.
What the repair involves
Cut back to sound material. The delaminated area is removed, and the cut is taken back to where the stucco is genuinely bonded, which is why the repair area ends up larger than the damage.
Inspect the paper and lath. This is the part that decides the price. Sound paper and lath means rebuilding the cement coats only. Rusted lath or deteriorated paper means new paper and lath first, and where water has been in the wall a long time, framing gets checked too.
Rebuild in coats, properly, allowing each to cure rather than rushing it.
Match texture and colour. Which is craft work and is worth discussing before the job rather than after. See colour and texture matching.
$500–$2,000 typical, or $8–$15 per square foot. Area, height, access, and what is behind the stucco drive it. Published on the pricing page and priced by the cost calculator.
Why this happens here
Water gets in at the parapet or a crack, and then this climate does the rest:
Freeze-thaw on a saturated wall. Water behind stucco freezes, expands, and pushes the stucco off the lath. This is the mechanism, and it is why delamination is far more common here than in the low desert.
Thermal cycling working the bond every day.
Monsoon soaking a wall that spends most of the year bone dry, so the wetting is sudden and heavy rather than gradual.
That sequence is also why spring is the right time to deal with it: a wall with water behind it going into winter will be worse by March.
If it is EIFS rather than traditional stucco
Synthetic stucco, foam board with a thin acrylic finish, behaves differently and fails differently. It is softer, it dents, and damage tends to be impact-related or moisture behind the foam. The repair is a different material and a different method, and getting that wrong is visible forever. The Synthetic and EIFS systems exist here too and repair completely differently from traditional three-coat, so establishing which you have is the first question on any quote.
What to expect on the call
Photos of the damage, a photo from further back showing where it sits on the house and what is above it, and your tapped-out estimate of the hollow area in square feet. Include the house’s age and whether the wall has been repaired before. We cover Casa Grande, Coolidge, Eloy, Arizona City, Florence, and Maricopa.
Frequently Asked Questions
What does it mean when stucco sounds hollow?
The stucco has separated from the lath behind it. Tap a sound wall and it is solid and dull; tap a delaminated area and it sounds drummy. That separation is nearly always caused by water that got behind the stucco, and the hollow area is usually larger than the visible damage.
Can hollow stucco just be coated over?
No, and this is the most common bad repair on Pinal County walls. A coating over delaminated stucco has nothing sound to bond to, so it comes off with the stucco underneath, usually within a season or two. Delaminated areas have to be cut out and rebuilt.
What does patching cost?
$500–$2,000 for typical patching work, or $8–$15 per square foot, which covers cutting back to sound material, new paper and lath where needed, and rebuilding in cement coats. The variables are area, height, access, and whether the paper and lath behind are salvageable.
Why is the hollow area bigger than the damage I can see?
Because water spreads behind the stucco before the surface fails. By the time a blister or a hole appears, the delamination usually extends well beyond it. Sounding the wall with a knuckle or a plastic hammer maps the real extent, which is why it comes before any honest quote.