How Effective Is Waterproofing Stucco?

Stucco is a popular choice for covering exterior walls, which makes waterproofing stucco a necessity. Stucco is commonly used over concrete walls and can easily be painted any color. Stucco is water resistant by design, but any crack or imperfection in stucco could allow water in, which means that stucco is not waterproof. There are several methods that one can use to waterproof stucco, all of which have their benefits and drawbacks. The most reliable option for waterproofing stucco is to use a waterproof barrier behind the stucco and then apply a waterproof paint or sealant over the stucco. Here are some methods to waterproof the stucco and keep water out of your house.

One method that could be used to waterproof stucco is simply applying waterproof paint. This method is by far the easiest, but can be the least reliable as well. If any paint chips or becomes damaged, then the waterproofing qualities of the paint and stucco have been compromised.

Step 1 – Clean the Stucco

You need to clean the stucco first with a soap and water mixture to remove all dirt and debris.

Step 2 – Paint Stucco

All you need to do is apply the waterproof paint directly onto the dry and clean stucco and allow to air dry.


You can also use a clear sealant to waterproof your stucco. You can apply the sealant over dried paint or directly onto the stucco. A separate sealant is more reliable as a waterproofing method than simply waterproof paint.

You can apply a clear waterproof sealant in the same manner as you would apply paint. Simply paint the sealant onto the stucco and allow it to air dry.

Waterproof Barrier

A great way to add waterproofing to stucco is to waterproof before you apply the stucco. By using a waterproof barrier between the home and stucco, you add an additional layer of waterproof protection.

Step 1 – Clean Base Wall

You need to begin with a clean surface. Wipe the surface with a towel or broom to make sure all dirt and debris are removed.

Step 2 – Roll out Barrier

Waterproof barriers come in small rolls that have a plastic backing that covers the adhesive surface of the barrier. It is best to work with one roll at a time. Start with your first roll and unroll the barrier with the plastic facing upward. Remove the plastic cover from the back of the barrier, exposing the adhesive surface of the barrier.

Step 3 – Apply Barrier

Now pick up the barrier and flip the adhesive surface toward the wall and apply. Smooth over the barrier to make sure the entire roll has been pressed against the wall and has created a secure adhesion. You can repeat this process until the entire wall has been covered with the waterproof barrier.

Step 4 -Add Stucco

Once the barrier has been fully applied, you can apply your stucco directly on top of the barrier.

Repairing Stucco Walls

Stucco as a siding material has a well-deserved reputation as a practical option. Just some of the reasons people like stucco walls are its minimal maintenance requirements, looks (many people prefer the appearance of stucco over vinyl siding because it gives a home a unique look), and great wind blocking and insulation value. However, since stucco is a cement mixture and is very hard, it can crack or even get a hole if hit with a heavy blow like a tree branch. Fortunately repairing stucco is a job a competent DIY’er can take on with confidence with quite likely the hardest part being color matching the old stucco and the repair. Here’s how to repair a stucco wall.


Thin cracks are usually quite easy to repair and should be fixed before they become bigger. Often very fine cracks can be filled and hidden by a coat of exterior acrylic paint color matched to the original stucco color.

Cracks too thick to be filled with paint can usually be repaired with exterior latex (paintable) caulk. Choose a caulk close in color to the original stucco to fill the crack then allow it to dry before painting over the repair with color matching paint. Putting some sand on the caulk while it’s still wet can help it blend with the surrounding stucco and give it a rough surface similar to the original stucco.

Cracks too big to be fixed with caulk can be repaired using either premixed acrylic stucco patching compound available at home and hardware stores or mixing and applying the same stucco mix that was originally applied to the wall.


Repairing a hole in a stucco wall will require a little patience and some practice. The hardest part is probably going to be matching the appearance of the original stucco. Try mixing some small batches of stucco tinted to closely match the original. Applying the different batches to small boards will allow you to figure out which mixture comes closest to being a match.

After determining the proper stucco mixture the next step is preparing the damaged surface to accept the repair. Start by removing any loose pieces of stucco in the hole and it’s often a good idea to also remove some undamaged stucco around the hole to be sure you will be applying your repair to a solid wall. Use the blower outlet on a shop vacuum to get rid of any dust left behind.

If the underlying wire mesh or tar paper has been damaged you will need to get cut out the damaged area and install and firmly fasten new paper and mesh before you start.

Apply your patch in layers, first filling the hole about half full then allowing the stucco to partially dry before drawing horizontal lines in the moist repair with a pointed piece of metal. After the first layer has dried apply a second coat to within 1/8 inch of the surface and once again give it time to dry. Finish the repair by applying and texturing the final coat.