Stucco is a popular home siding material for a reason—it can last for hundreds of years. But that durability doesn’t mean you never need to repair it to keep it looking its best. If you notice cracks, holes, or fissures in your stucco siding, you should address them quickly before water seeps in and causes mold, mildew, or rot to form behind the mesh.
Not sure how to fix your stucco? Stucco repair is a fairly simple DIY project, but you can always call in a stucco professional to patch damage that’s widespread or out of reach. Stucco repairs can cost as little as $250 for a small repair and as much as $5,000 for extensive work.
Why You Shouldn’t Wait to Repair Stucco
Beyond being decorative, stucco acts as a shield around your home. As long as it’s intact, the cement mixture is impermeable to the outdoor elements. When mastering how to repair stucco cracks and holes in the stucco, open your home up to the outside, allowing moisture to enter behind the remaining stucco.
Trapped moisture can cause mold and mildew to grow and result in rot, which is a much more costly and challenging fix than patching broken stucco.
When preparing to fix your stucco, pick a day with relatively warm temperatures. Stucco should only be applied when the temperature is between 40 and 90 degrees Fahrenheit. Cold weather can cause stucco to run. You should also avoid patching stucco in hot, dry weather because it could cause the water in stucco to evaporate too quickly, not allowing the material time to cure.
Preparing to Repair Stucco
To prepare for stucco repairs, it's helpful to gather the necessary tools and materials referenced above. Before you kick a patching project off, take a moment to clean the damaged area using the wire brush. Remove any loose debris to ensure a smooth fix. Next, make sure the surrounding stucco is moist by lightly spraying it with water. This will help the new stucco adhere properly. Lastly, ensure you have good ventilation and protect yourself by wearing gloves and goggles.
Remove Loose and Damaged Stucco
While wearing gloves and eye protection, use a masonry chisel and hammer to carefully remove loose and damaged pieces of stucco. Continue removing damaged material until you see the wire mesh lathing underneath it. Clean the mesh with a wire brush to ensure there aren’t any small pieces left.
Next, inspect the lathing for damage. If it’s damaged or has rust or corrosion, remove the section with wire cutters and replace it with new lathing.
Cover Any Exposed Lath
When covering or recovering exposed lath with builder's paper, start by assessing the severity of the stucco damage. If the lath is exposed, it's crucial to protect it with builder's paper. Begin by removing any loose or damaged paper and then cut a piece of builder's paper to fit the exposed area, making sure it overlaps the intact paper around it.
Next, you’ll secure the builder's paper using construction staples or adhesive, ensuring it is taut and smooth. This will provide a barrier between the lath and stucco, preventing further damage and ensuring a solid foundation for the new stucco application.
Replace Metal Mesh (If Damaged)
To replace the metal mesh for stucco adhesion, start by assessing the condition of the existing mesh. If it's severely damaged or missing, replacement is necessary. Begin by removing any remnants of the old mesh. Measure the area that requires new mesh and cut a piece of galvanized metal mesh to fit. Secure it tightly against the structure using corrosion-resistant screws or staples, ensuring it is flush with the surface. Ensure proper overlap with the existing mesh if applicable. This new mesh will provide a strong foundation for the stucco to adhere to during application. If the existing mesh is mostly intact, you can skip this step.
Mix Your Stucco
It’s best to mix your stucco according to the manufacturer’s instructions. The color of stucco changes over time and with exposure to the elements, making it difficult to achieve a perfect match when patching. To address this, you have options for adding color to the stucco mixture.
One approach is to add pigment to the wet stucco mix before applying it. Pigments are available in various shades and can be mixed according to the manufacturer's instructions to achieve the desired color. Alternatively, if your siding is already painted, you can paint the repaired section once it's dry to match the existing color. Experimentation and testing are advised to achieve the desired color outcome.
If you don’t have the manufacturer’s instructions available to you, you can follow the specific proportions for mixing stucco outlined in the ASTM C926, which is the Standard Specification for Application of Portland Cement-Based Plaster. According to the standard, the recommended mixture ratios are as follows for the different coats (which you can enhance by using slightly different mixture ratios each time):
Scratch coats: 1 part cement to 2-1/4 to 4 parts sand.
Brown coats: 1 part cement to 3 to 5 parts sand.
Finish coats: 1 part cement to 1-1/2 to 3 parts sand.
These proportions provide guidelines for achieving the desired consistency and strength for each coat of stucco. Following these ratios is important to ensure the proper application and durability of the plaster.
Apply the First Coat of Stucco
With a masonry trowel, apply a thin layer of stucco, about one-fourth of an inch, to the wire mesh. Completely cover the lathing. Wait a few minutes and allow the stucco to begin to harden.
Once it looks dry, use the notched side of the trowel to score grooves over the entire surface. The scoring will provide a better surface for the next coat and result in better adherence. Cover the patch with plastic and secure it with painter’s tape, allowing it to cure and dry without being exposed to bad weather.
Apply the Second Coat
After at least 24 hours, remove the plastic. If the stucco is not dry, recover and wait until the patch is dry before proceeding. Once the patch is dry and has lost its wet-looking sheen, mist it with water or dab the area with a wet sponge. Be sure to moisten the edges of the existing stucco, too.
The next step is to apply the second coat of stucco. Begin working from the bottom of the patch and then move up, spreading a layer of stucco that is three-eighths of an inch thick. Allow the layer to begin to dry, and then smooth out the surface using a masonry trowel. Cover the layer with plastic and wait until the patch is dry.
Apply the Finish Coat
Once the patch is dry, remove the plastic. Moisten the patch and the edges of the existing stucco, and then apply a layer that is flush with the surrounding area. Use your finishing tool to add texture to the patch that matches the original.
After applying the final coat, wait several days for your patch to cure. Then, if you did not add pigment during the mixing process, paint your patch. You may have to paint the entire wall to obscure the repair area completely.
DIY vs. Hiring a Pro
Stucco patching is a relatively straightforward DIY project, but in certain instances, it may be beneficial to know who to call for stucco repair. If the stucco damage is extensive or in a difficult-to-reach place, like near the roofline, you might consider hiring a stucco repair pro. Professional stucco repair costs around $1,600 on average.
Improperly patched stucco can also lead to even more costs down the line, such as internal damage to your home’s structure or mold growth due to trapped moisture underneath.
Frequently Asked Questions
Stucco siding alternatives that offer a similar combination of durability, versatility, and longevity include fiber cement and EIFS (Exterior Insulation and Finish System), or “synthetic stucco.” Fiber cement can look like various materials—like wood or stone—and offers extra resistance to weather and pests. EIFS is a more durable and versatile alternative that is ideal for homeowners who want to elevate their curb appeal beyond traditional stucco siding.
The curing time for stucco typically takes several weeks to fully complete. During the curing process, the stucco undergoes a chemical reaction and gradually hardens. It's important to note that curing is different from drying. While the surface of the stucco may dry relatively quickly within a few hours or days, the curing process continues beneath the surface, strengthening and solidifying the stucco.
It's best to avoid excessive moisture exposure during the curing period, as it can impede the curing process. The exact curing time can vary based on factors such as temperature, humidity, and the specific stucco mixture used.
It is possible to paint stucco siding. Painting stucco offers the advantages of providing a refreshed appearance and matching the patched area with the rest of the painted structure. However, there are some considerations to keep in mind.
Painting the entire structure, including stucco patches, can make it more challenging to reapply stucco in the future if desired. Stucco is a breathable material that allows moisture to evaporate, while paint can create a barrier, potentially trapping moisture.
To minimize these risks, it's important to choose high-quality breathable paint and ensure proper surface preparation. Before deciding to paint stucco, careful consideration should be given to the long-term implications and desired aesthetic.
When choosing paint for stucco, it's recommended to use a high-quality exterior paint specifically formulated for masonry or stucco surfaces. Look for paints labeled as "masonry paint," "stucco paint," or "concrete paint." These paints are designed to adhere well to stucco surfaces and provide durability and weather resistance.
Opt for paints with good breathability to allow moisture to escape and prevent potential issues with trapped moisture. You may also want to consider paints with UV resistance to protect the stucco from fading or discoloration due to sun exposure.
Jacqueline DeMarco, a Northern California-based freelance writer specializing in sharing home decor and DIY tips, particularly focused on organizing and decorating small spaces. She has contributed to sites like Apartment Therapy, The Everygirl, and Orchard.
Jacqueline DeMarco, a Northern California-based freelance writer specializing in sharing home decor and DIY tips, particularly focused on organizing and decorating small spaces. She has contributed to sites like Apartment Therapy, The Everygirl, and Orchard.
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