Can You Stucco Over Slump Block? (Explained)

Because of their structural diversity and elegance, slump blocks are a common building material. Slump blocks are a type of concrete that is usually removed from the mold before it sets.

The slumped design looks great and can be easily combined with other wall systems. You can find slump blocks in a wide range of weights and colors. However, despite offering homeowners many benefits, the slump block trend is gradually fading.

Stucco is an ideal option if you have slump block walls and want to revamp the design. Stucco was once a signature finish for Spanish architecture. However, these days, this finish has been adapted worldwide.

Stucco is a mixture of sand, lime, Portland cement, and water. It’s a finish that is applied as the final coat on walls. Stucco looks great, and it’s durable. But can it be used over a slump block? That’s what we are going to address.

White stucco texture

Is Stucco Compatible with Slump Block?

Stucco is extremely compatible with slump blocks because they are made from the same ingredients. Construction agencies permit the application of stucco directly to concrete slump blocks as long as enough prep work is performed to ensure adhesion.

Therefore, if you were wondering whether you can stucco over slump block, you have a green light to revamp the aesthetics of your home using this product.

Which Type of Stucco is Ideal for Slump Block?

If you have done more research about applying stucco over slump blocks, you are aware that there are three main types of stucco. You need to use the correct type of stucco on slump blocks to ensure the longevity of the project.

The best type of stucco to use on slump blocks is the 2-coat system. This system entails using a bonding adhesive on the concrete slump blocks before installing two coats of stucco.

There are other types of stucco, such as the 1-coat system, which is ideal for rigid foam boards. You should also know about the 3-coat system, which is quite time-consuming and labor-intensive because it requires the installation of asphalt-infused paper, wire, and stucco.

When sourcing stucco to apply over the slump block, go for the 2-coat system for optimal results.

How to Apply Stucco over Slump Block?

The fact that these two materials are compatible shouldn’t mislead you to think it’s an easy project. If you are working on a big slump block wall, make sure you are physically and emotionally prepared to work.

If you can get an extra set of hands, you will be able to work faster. Anyway, here is a step-by-step guide on how to stucco over slump block.

Step 1 – Clean the Surface

If your slump block walls have been around for a while, they must be thoroughly cleaned. A pressure wash is sufficient to eliminate any stubborn dirt and impurities. Slump block walls that have been around for longer can be sandblasted.

Step 2 – Brush a Concrete Bonding Agent

Earlier, we mentioned that the 2-coat system is best for applying stucco over concrete slump blocks. Therefore, brush a concrete bonding agent over the slump block to begin the installation.

There are different types of concrete bonding agents, such as latex emulsions and polyvinyl acetate (PVA). Identify a suitable bonding and brush it over the slump block.

Step 3 – Apply the First Coat

Once the bonding agent dries, you can proceed to apply the first coat of stucco. The scratch or first coat should be at least ½” or ¼” thick. Give it time to harden.

Step 4 – Sand the First Coat After 36 Hours

Sanding is crucial as it gives the final coat something to adhere to. Within 36 to 48 hours, you should sand the first coat.

However, don’t over-sand the first coat to anything less than 1/8″ thick. Keep the first coat wet during this period by misting it with some water.

Step 5 – Apply the Second and Last Coat

To wrap up the stucco application process over the slump block, finalize by applying the last coat. The ideal thickness should be 1/8″ to 1/4″. In the last coat, you can add powdered pigments to get a colored finish.

During this last stage, you can also determine the ideal texture. The last coat should cure within two days. Don’t forget to water it regularly.

The curing stage for stucco is very important as it determines the quality of the finish. You need to ensure that the stucco is moist.

Can Stucco Co-exist Alongside Slump Block?

One of the benefits of stucco is that it can blend well with other wall finishes. If you want stucco on some walls and retain slump blocks on others, these two designs can peacefully co-exist without affecting the exterior aesthetics of your property.

Therefore, feel free to cover some slump blocks with stucco and some without to create a unique design.

Slump blocks

Is a Steel Mesh Necessary When Applying Stucco Over the Slump Block?

When researching methods to apply stucco over slump block, you may come across recommendations about using a wire mesh to promote adhesion. Is the steel mesh necessary?

First, you must understand that stucco and slump blocks are made from the same materials. Therefore, the rate of compatibility between these two products is high. That eliminates the need for a wire mesh.

Also, stucco has something it can adhere to because of the slumped design of slump blocks. Not forgetting that the method I have shared with you entails using a concrete bonding agent. It will be enough to ensure the adhesion of stucco over slump block walls.

However, we can’t dismiss the added advantage of using a wire mesh because its presence enhances the adhesion of stucco to slump blocks.

The purpose of the wire mesh is to create a textured surface for the stucco to adhere to. This reinforces the wall structure, ensuring these two materials are well-bonded.

Though a wire mesh enhances the bonding strength and rigidness, it requires a lot of work. Unlike a concrete bonding agent that only needs to be brushed, a wire mesh has to be screwed to the slump block.

You can only imagine how difficult drilling into a slump block is. The good news is that if you use a steel mesh, there is no need for a bonding agent.

The other thing is that the stucco will be way thicker than using a bonding agent. It’s up to you to weigh both options and evaluate which is more ideal.

How Long Does Stucco Last Over Slump Block?

If you thought that slump block was durable, wait till you meet stucco. Stucco can last over fifty years over slump blocks if properly applied on a well-prepared surface. That’s a long duration that you won’t get from other types of siding, such as wood and PVC.

To ensure longevity, the stucco should be maintained occasionally. You don’t have to worry about maintenance costs because they are very low.

Will Stucco Add More Insulation to Slump Block Walls?

Way back when slump blocks were used to build homes, electricity was affordable. Therefore, they are not designed to offer much insulation.

The good news is that applying a layer of stucco over your slump block walls adds more insulation. You will realize significant savings in energy bills.

The stucco will also limit noise from passing through. Other than beauty, stucco also offers insulation benefits.

Can I Install Stucco Over Slump Block By Myself?

These days, anything is possible, especially if you are an ambitious DIY enthusiast. Above, we have shared a guide on how to install stucco over slump blocks.

It’s a project you can pull off by yourself, especially if you choose the easier route that entails using a bonding agent.

However, I would like to warn you that installing stucco, especially over a significant area of slump block, is easier said than done. It’s time-consuming, laborious, and requires some level of professionalism.

The idea of paying someone to install stucco over slump blocks may not sit right with you. But it is 100% worth it.

The installation costs are also a little bit steep. You may want to research and compare the costs of various installers.

Does Stucco Applied Over Slump Block Crack?

Cracking is an issue that may occur on stucco applied to the slump block. There are various causes for cracking. First, if there is any movement that is experienced on the foundation, cracking may occur.

You can also spot cracks in wall intersections. Control joints should be installed on the corners when applying stucco over slump blocks. This will prevent the development of cracks.

Another reason you should hire an expert to install the stucco over the slump block. Also, if cracks in your slump blocks aren’t fixed, they can affect the stucco.

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