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Stucco Cracks and Repairs: Hairline vs Structural, What Each Crack Is Telling You, Patching Acrylic Stucco, Recoating a Whole Elevation, and What Each Repair Costs in Ontario
Exterior Finishes
Stucco Cracks: Most of Them Are the Wall Telling You It Is Fine, a Few Are the Wall Telling You to Look Underneath, and the Patch Never Matches
Every stucco wall in Ontario has a crack somewhere, and the first thing to do is not call anyone. Stucco is a thin, rigid skin over a wall that moves with the seasons, and a hairline at a window corner is that movement arriving at the surface. What matters is the width, the direction and whether it is getting longer. A crack you cannot fit a credit card into is a cosmetic job. A crack you can see daylight through, or one that steps like a staircase, is a question for the foundation. And a crack with a brown stain under it is not a crack problem at all. Here is how to tell them apart and what each one costs to fix.
Reading the crack
| What you see | What it usually is | What to do |
|---|---|---|
| Hairline, under 1/32 in., running diagonally from a window or door corner | Stress at the opening. Framing shrinkage on wood frame in the first two years; a missing diagonal mesh strip on acrylic. Normal. | Watch it. Seal it with elastomeric sealant if it bothers you. Recoat when the elevation is due. |
| Fine random network over a whole wall, like a dry riverbed | Map cracking. Cement stucco that cured too fast, too thin, or without control joints. Cosmetic, but it lets water in on a wall with no drainage behind it. | Elastomeric recoat of the elevation. Add control joints if the wall has none. |
| Straight horizontal crack at a storey line or above the foundation | The floor framing shrinking against the stucco, or the sill plate. On a two-storey wood-frame house, almost expected. | Cut a control joint in at the line, $6 a foot, and recoat. |
| Crack wider than 1/8 in., or one side higher than the other, or stepped | Movement in the structure: a settling footing, a lintel that is sagging, a deck ledger pulling. The stucco is reporting it, not causing it. | Find the cause before touching the stucco. A structural look at the foundation first. |
| Crack with a brown or black stain below it, or stucco that sounds hollow when you knock | Water. The stucco has let go of the base, or the sheathing behind it is wet and swelling. On wood-frame EIFS from the 1990s, assume the worst until tested. | Moisture test, then the moisture behind stucco page. |
| Dents, gouges, a hole with foam showing | Impact. The lawn mower, a ladder, a hockey puck. Acrylic stucco is 1/8 in. thick over foam. | Cut and patch, and accept the patch will show until the elevation is recoated. |
Photograph every crack with a tape or a coin in the frame, write the date on the photo, and look again in six months. A crack that has not grown is not growing. A crack that has is a different conversation.
Why the patch never matches
Acrylic stucco finish is troweled and floated on in one pass per wall, and the texture comes from the aggregate in the finish and the way one person’s float moved over it on one afternoon in one humidity. A patch is a different afternoon, a different wrist, a finish from a different batch, on a wall that has faded for ten years. It will match in the way a new tire matches the three old ones. From the street, a good patch is invisible in a year; from the walkway, it is a patch forever.
That is why the honest advice on a small repair is usually to wait and bundle it. Collect the cracks and dents on an elevation until the elevation is due for a recoat anyway, patch them all on the same day, and recoat the whole wall so there is one texture and one colour. On an ICF house that day comes later, because the wall is not moving under the stucco; the stucco on ICF page explains why there is so little to patch.
The repairs and what they cost
Seal a hairline. Clean it, run a bead of paintable elastomeric sealant into it, tool it flush, dab finish over it. An afternoon and a tube. If you are paying someone, you are paying a service call, not a stucco rate, and the stucco trades do not come out for it; a handyman or painter will.
Recoat an elevation, $3.50 a square foot, two coats. This is the repair for map cracking, faded colour, a dozen sealed hairlines and a wall that just looks tired. The wall is washed, cracks are sealed, and two coats of elastomeric or acrylic coating go on with the texture retained. A 600 sq ft side elevation is $2,100; a whole 2,400 sq ft house is $8,400 before HST. It is a painter’s job as much as a stucco job and it is on the exterior painting and staining page as well.
Cut out and replace an area, $21 a square foot. For hollow stucco, impact damage bigger than a fist, or a wall section that has let go. Cutting the old stucco out is $6.00 a square foot, new acrylic stucco at the wood-frame mid rate is $15, so $21 on the area replaced, and the mesh has to lap 2.5 in. onto sound stucco around it. A 40 sq ft area under a window is $840 of work, and then the elevation needs a recoat to hide it, so call it $840 plus $2,100 on a 600 sq ft wall. On ICF the new stucco is $13, so $19.
The minimum. A stucco crew has a $3,500 minimum, the same as a stone crew, because the scaffold, the mixer, the mesh and two people for a day cost that before the first trowel. One crack is not a job for them. One elevation is. Plan the repair around that number and you will not be surprised by it.
Over old cement stucco: a full acrylic skin. When a cement stucco wall is cracked everywhere but sound and bonded, the crew seals the cracks, primes, and puts a new base coat with mesh and an acrylic finish over the whole wall. It is priced at the acrylic rate on wood frame, $15 at mid, without the tearoff, and it turns a 1960s wall into a wall that behaves like acrylic. The three systems page covers why that works.
When the crack is the house
A crack that is wider at the top than the bottom, that runs from a foundation corner up to a window, that steps along the block coursing of a foundation, or that has one edge proud of the other, is the structure moving. Stucco repair on a wall that is still moving is money thrown at the crack, and it will be back by spring. The order is: find out why the wall moved, fix that, wait a season to see that it has stopped, then fix the stucco. Foundation types in Ontario explains which foundations move and why.
On a house under Tarion, a stucco crack in the first year is a cosmetic item the builder owns, and a crack caused by settlement is a major structural item for seven years. Photographs with dates are what turn a complaint into a claim. And on a house you are buying, a stucco elevation that was recoated last month is the one to put a moisture meter on, because recoating hides stains as well as cracks. The moisture inspection page says what that test costs and who does it.
Questions people ask
Are hairline cracks in stucco normal?
Yes. Diagonal hairlines from window corners on a wood-frame house in its first two years are the framing drying out. On cement stucco, a fine network is the cement curing. Neither is structural. Seal them and recoat when the wall is due.
When is a stucco crack serious?
Wider than 1/8 in., one side higher than the other, stepped like stairs, growing between two dated photographs, or stained underneath. The first four are movement in the structure; the last is water. Both need a look behind the stucco before any repair.
How much does it cost to repair stucco?
A sealed hairline is a tube and an afternoon. Recoating an elevation is $3.50 a square foot, about $2,100 for a 600 sq ft wall. Cutting out and replacing damaged stucco is $21 a square foot on the area, and a stucco crew has a $3,500 minimum, so bundle the repairs.
Can you patch acrylic stucco?
Yes, but the patch will not match the texture or the faded colour around it. Patch the damage, then recoat the whole elevation if you want it invisible. The patch itself is sound; it is the look that is the problem.
How often does stucco need to be recoated?
Acrylic every 20 years or so, when the colour has faded or the cracks have added up. Cement stucco wants paint or a fog coat every 10 to 15 years. Recoating at $3.50 a square foot is a fraction of new stucco at $15.
Price the repair, or the recoat
The exterior cladding cost calculator prices a recoat, a cut-and-replace area and a full re-stucco side by side so you can see where the $3,500 minimum makes the bigger job the better buy. If a contractor has quoted you a stucco repair that looks like the price of a new wall, the $99 review will read it against these rates and say whether it is.
Sources and further reading
- Dryvit: EIFS and acrylic finish systems: what a drained EIFS assembly is, the base coat, mesh and finish, and the details at openings.
- Canada Mortgage and Housing Corporation: the Canadian wall-assembly and moisture research behind rainscreens and the second plane of protection.
- Tarion warranty coverage: what a new-home warranty covers for cladding, stucco cracks, masonry and water penetration in years one, two and seven.
