Stucco Crack Repair Products: The Right Filler for Each Crack

First, Size Up the Crack

Stucco is a cement plaster, and cement is rigid, so some cracking comes with it. The Stucco Manufacturers Association says the occasional hairline crack in cement plaster "is not detrimental, nor should it be considered a defect." What decides the product is the crack's width and whether it moves.

Parex, one of the larger stucco makers, draws the first line at 1/32 inch, about the thickness of a credit card. Cracks that thin are mostly a looks problem. Wider cracks can let rain into the wall over time, which is why they're worth sealing.

Hairline Cracks: Often Just Paint

One or two hairline cracks can be filled with the textured sealants in the next section, or left alone.

A web of fine cracks across a wall is a painting job. Parex's repair bulletin calls for two coats of elastomeric coating over the area, carried to a corner, edge or other natural break so the repair doesn't show as a patch. Elastomeric paint goes on thick and stretches, so it bridges hairline cracks that regular house paint would show. For the step-by-step, see our guide to fixing hairline cracks in stucco.

Small Cracks: Textured Elastomeric Sealant

Stucco walls swell and shrink a little as they heat up and cool down, and a crack opens and closes with them. A filler that dries hard cracks again. An elastomeric one stretches, and a textured one blends into the wall instead of leaving a smooth stripe.

Sashco Mor-Flexx

Mor-Flexx is a sealant made for textured surfaces: stucco, mortar, stone and EIFS. Sashco says its texture "mimics that of real mortar and stucco" and that it stretches like rubber instead of cracking.

• Colors: gray, white, beige, charcoal and ironstone, in 10.5 oz tubes, so unpainted stucco can often go unpainted.
• Painting: with exterior latex paint after 4 hours.
• Weather: apply when the wall is dry and between 40°F and 120°F, and allow 1 to 3 days before direct rain.
• Deep cracks: Sashco says to press foam backer rod into joints deeper than 1/4 inch first.
• Not for: concrete less than 6 months old, surfaces under water, or areas with heavy foot or vehicle traffic.

Best for: cracks in unpainted or color-coat stucco, where matching the color matters.

DAP Elastopatch Textured

Elastopatch is an elastomeric patching compound with a textured finish for stucco, masonry and brick. DAP says it "eliminates reoccurring cracks by providing a permanently flexible fill."

• Size: DAP's how-to guide puts it at cracks up to 1/4 inch wide and 1/2 inch deep, in layers for anything deeper.
• Texture: shape it before it dries with a putty knife for smooth, a rubber float for rough, or a stiff brush for very rough. It can't be sanded afterward.
• Painting: wait at least 24 hours, prime, then paint.
• Color: off-white, in a 10.1 oz tube, a quart or a gallon.

Best for: painted stucco, and cracks that came back after an earlier fix.

Chips and Shallow Holes: Premixed Stucco Patch

For missing stucco, a tube doesn't hold enough. A premixed stucco patch is sanded so it takes on the wall's texture.

QUIKRETE Pre-Mixed Stucco Patch (No. 8650)

A ready-to-use acrylic latex patch for cracks, breaks and holes in stucco. QUIKRETE says it "blends with the texture of surrounding stucco" and repairs damage up to 1/4 inch thick. It comes in a 1-quart pail.

DAP All-Purpose Stucco Patch

DAP says it fills holes "as wide as your palm and up to ½ inch deep." Anything deeper than 1/4 inch goes on in two or more layers, each one dry before the next. Smooth it with a wet rubber float, and for texture, dab it with a brush or toss a little sand onto the wet patch. It dries in about 72 hours, depending on the weather and thickness. Then prime and paint.

Both patches are for the stucco's surface. If a hole goes through to the wire lath or the block, or the stucco around it is soft or loose, it's a repair for a contractor (see When a Tube Isn't the Fix).

Gaps at Windows, Doors and Trim: Paintable Caulk

Where stucco meets a window frame, a door frame or trim, the joint needs a caulk that seals two different materials.

DAP Alex Plus

An acrylic latex caulk with silicone, for inside and outside. DAP lists window and door frames, molding and trim among its uses.

• Size: joints up to 1/2 inch wide and 1/2 inch deep. Deeper joints get foam backer rod first.
• Painting: with latex or oil-based paint in 30 minutes.
• Weather: apply above 40°F, and not when rain is due before it cures.
• Durability: DAP backs it with a 40-year guarantee.

Alex Plus dries smooth, so keep it to the joints. Run across a textured wall, it shows as a smooth line. Polyurethane sealants are tougher in joints that move a lot, but they're stickier to work with and don't clean up with water. Follow the label for any primer they need on stucco.

How to Apply a Stucco Crack Filler

You'll need the product, a caulking gun, a stiff brush, a putty knife or rubber float, a damp sponge, a bucket of water, and foam backer rod for deep cracks.

1. Pick a dry day above 40°F with no rain due for at least a day. In a Florida summer, that often means starting on a dry morning, well ahead of the afternoon storms. Mor-Flexx needs 1 to 3 days before direct rain.
2. Clean out the crack. Brush out loose stucco, dust and any old caulk. The crack should be clean and dry.
3. Fill the depth. For a crack deeper than about 1/4 inch, press foam backer rod in first so the sealant isn't too thick.
4. Push the bead into the crack. Cut the nozzle to about the crack's width and press the sealant in, not just over the top.
5. Match the texture while it's wet. Dab it with a damp sponge or stiff brush, or float it with a wet rubber float, and wipe any extra off the wall.
6. Let it dry for the time on the label. That's 4 hours for Mor-Flexx under latex paint, a day for Elastopatch, and about 3 days for DAP's stucco patch.
7. Prime if the label says to, then paint. Painting the whole section of wall, corner to corner, hides a repair better than a spot of new paint.

This short video shows the basics of filling a stucco crack:

Video: "Repairing Stucco Cracks" by FreedomToFix on YouTube. Follow the label of the product you use for drying and painting times.

When a Tube Isn't the Fix

Some cracks need more than a filler. None of these mean a wall is failing. They mean the repair goes deeper than the surface, and someone should see it in person:

• A crack wider than 1/4 inch, or one where one side sits higher than the other.
• A crack that opens again in the same spot after a flexible filler.
• Stucco that sounds hollow when tapped, feels soft, bulges, or has blistered or bubbled paint. Parex says blistering is often caused by water that got behind the finish, and that cause gets fixed before the finish does.
• Cracking spread across a whole wall, which usually calls for resurfacing rather than patching.

Your local Stucco HQ contractor looks at the wall in person and gives you a free written estimate. See how a stucco crack repair works, or what affects stucco crack repair cost.

What Changed Since Our 2018 List

The first version of this page, in January 2018, listed five products. Three are off the list now:

• Sashco Through the Roof! is a clear sealant made mainly for roofs. It seals, but it doesn't take on stucco's texture.
• Loctite PL Premium Fast Grab is a construction adhesive for gluing materials together, not a crack filler.
• Red Devil 0646 is a masonry and concrete sealant, made for steps, sidewalks and mortar joints. The stucco products above blend in better.

Mor-Flexx stayed at the top. DAP Alex Plus stayed too, now for the job it does best: joints at windows, doors and trim.

Frequently asked questions