Waterproof Expert

Waterproofing tips & tricks

Is Stucco Waterproof? It’s Not, but You Can Improve It

Ever looked at a stucco wall and wondered if it can handle a good splash? Well, let’s talk about whether stucco is waterproof or not.

Stucco is moisture-resistant to a degree, but it’s not completely waterproof due to its absorbent nature. It allows some water, like rain, to permeate.

The good news is that you can enhance its water resistance by applying a sealer.

What Is the Best Way to Waterproof a Stucco Wall?

Step 1: Fix the Cracks

Stucco is great, but over time it might show some cracks. Grab a tube of acrylic caulk from your local hardware store and patch those little crevices up.

Just squeeze a bit of the caulk into the crack, and then smooth it out with a putty knife, a spoon, or a rag.

Easy peasy!

Step 2: Give it a Clean

Next, you need to get rid of any dirt or dust on your stucco wall. You’ll need a power washer for this.

You can rent one of these from many hardware stores. Give the wall a good, thorough wash, and then let it dry completely.

Drying can take a few days.

Step 3: Apply the Sealer

You can use a siloxane-based sealer to waterproof stucco. Take that sealer and paint it on your wall. You can use a regular paint roller or a garden sprayer, whichever you prefer.

Just make sure to cover the entire wall.

Siloxane-based sealers are great because they penetrate into the stucco and provide a barrier against water without changing the look or color of your wall.

RainGuard’s Premium Stucco Sealer is an excellent choice.

As the manufacturer explains:

This sealer is formulated with a water-based silane and siloxane blend to provide superior protection against wind-driven rain, mold, mildew, and other moisture damage. The penetrating formula means no film is created and the surface will not change in texture or appearance.

Always follow the manufacturer’s instructions on the can for the best results.

Step 5: Let it Dry

Let everything dry completely. This can take a few days, depending on the weather.

Be patient. Rushing might ruin all your hard work!

And there you have it! You’ve just waterproofed your stucco wall.

Just by following these steps, you’ve increased the lifespan of your wall and made it weatherproof.

Good job, you!

How Can I Waterproof Stucco Cracks?

Here are the four steps for waterproofing stucco cracks.

1. Clean the crack using a wire brush or scraper to remove debris and ensure a clean surface.

2. Apply elastomeric caulk or stucco crack repair product into the crack, filling it completely. Smooth the surface with a putty knife or trowel.

3. Allow the crack filler to dry overnight.

4. Paint or seal the area to provide additional protection and blend it with the surrounding stucco surface.

Addressing cracks promptly will help prevent water damage and maintain the stucco wall’s integrity.

Can Water Leak Through Stucco?

Water can potentially leak through stucco walls if they’re not properly sealed or if there are cracks, gaps, or other areas of vulnerability.

Stucco itself is not inherently waterproof, but it can be made water-resistant through proper installation and maintenance.

Address any cracks or areas of concern promptly to prevent water from penetrating the stucco and causing potential damage to the underlying structure.

Does Stucco Need to Be Waterproofed?

It is highly recommended to waterproof stucco to protect it from water damage.

While stucco is a durable and long-lasting material, it is not inherently waterproof.

Without proper waterproofing, stucco can be susceptible to water penetration, which can lead to various issues such as cracking, mold growth, and structural damage.

Applying a suitable waterproofing product to the stucco, such as a penetrating sealer or elastomeric coating, can significantly enhance its resistance to water penetration.

How Do You Protect Stucco From Water Damage?

To protect stucco from water damage, regularly inspect your stucco walls for any cracks, gaps, or areas of damage. Repair any issues promptly using a high-quality elastomeric caulk or stucco crack repair product.

Consider applying a waterproof coating or sealer specifically designed for stucco surfaces. These coatings provide an additional layer of protection against water penetration.

Clear any debris, leaves, vegetation, dirt, mold, or mildew that may trap water against the stucco surface.

Can Rain Damage Stucco?

Rain can potentially damage stucco if the stucco is not properly installed, maintained, or protected.

Here are a few ways rain can damage stucco.

Moisture Absorption

Stucco is like a sponge and can soak up water. If the stucco isn’t sealed well or has cracks or gaps, rainwater can get inside and cause damage over time.

Cracking and Erosion

When it rains a lot or if the stucco stays wet for a long time, it can lead to cracks in the stucco. Water seeps into these cracks and makes the stucco weaker and crumble over time.

Mold and Mildew Growth

When it rains a lot and the stucco gets really wet, it becomes a good place for mold and mildew to grow.

Mold and mildew can make the stucco deteriorate, look bad, and they can even cause health problems.


Rainwater can cause efflorescence, a white powdery substance, to form on the surface of stucco.

This occurs when soluble salts are brought to the surface as water evaporates. Efflorescence can mar the appearance of the stucco.

Is Stucco Good for Wet Climates?

Stucco can work well in wet climates, but it requires proper installation, maintenance, and additional measures to ensure its longevity and performance.

It is crucial to waterproof stucco in wet climates to protect it from water damage.

Regular inspection and maintenance are essential in wet climates. Keep an eye out for cracks, damaged areas, or signs of moisture intrusion.

Promptly address any issues to prevent further damage.

How Long Does Stucco Last?

Stucco can last anywhere from 30 to 50 years with good maintenance and favorable conditions.

Most painting professionals recommend painting the exterior stucco every five to 10 years.

What Is the Biggest Problem With Stucco?

The biggest problem with stucco is typically moisture intrusion. Stucco, being a porous material, can allow water to penetrate through cracks, gaps, or improperly sealed areas.

This can lead to various issues such as water damage, mold growth, rotting of underlying structures, and deterioration of the stucco itself.

Will Painting Stucco Make It Waterproof?

Painting stucco can help improve its water resistance but it does not make it completely waterproof.

While paint creates a protective layer on the surface of the stucco, it is not a foolproof barrier against water penetration.

Stucco is naturally porous and can still absorb some amount of water even with paint applied.

Do I Need to Seal Stucco Before Painting?

It is generally recommended to seal stucco before painting it. Sealing the stucco surface helps improve paint adhesion, and enhances the durability of the paint job.

Stucco sealers act as a barrier against moisture penetration.

I hope this guide answered your questions.

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