Last Updated on June 5, 2022 by Jose Villegas Jr.
To stucco a concrete wall and blockwork, first, clean it and moisturize it if it doesn’t absorb any water or if the surface is contaminated. Then, before applying the brown coat, mix, apply and mark the scratch layer. A pigment or color can be used as the final layer.
What is Stucco?
Portland Cement Plaster (stucco) is a building material that is widely employed on both outdoor and indoor construction surfaces. Despite its price, it is extremely durable and does not rot easily, and is able to resist the growth of fungi well.
Additionally, it requires little maintenance which makes it an ideal exterior material in DIY-related projects.
Traditional stucco is constructed from lime and sand along with water. The stucco we use is today made from Portland cement along with sand and water.
The materials listed are combined to form the plaster, which can be sprayed on ceilings, walls, or any other structure in order to create an even, hard surface after it has dried and hardened.
Most of the time, you’ll need an expert to assist you with the stucco process but you can DIY it using proper methods. You can apply stucco to concrete wall systems, or on a frame structure.
Stucco is commonly used to protect concrete, cinder blocks, or adobe. It can also be used to cover clay brick or blockwork.
Benefits of Stucco
There are many advantages to using stucco. One advantage is you will reduce construction costs and still get a durable and long-lasting appearance. The material is flexible because it can be used in diverse conditions.
Other benefits are:
Fire-resistant
Color retentive
Available in different colors/pigments
Stucco’s disadvantages
Although stucco is a great product to give your home an update, however, it has its flaws.
For instance, stucco can be porous, meaning it’s not waterproof, therefore water may penetrate the substance slowly, leading to the stucco breaking down eventually. A prolonged period of exposure to water can also harm the frame of the house in the future.
The bright side is that homeowners can address the issue of water by finishing the areas of their homes that are in contact with water. So, the stucco is able to endure the rainy seasons.
Homeowners can enhance the footings on the bottom or top of their homes with different materials such as brick or vinyl.
Another disadvantage of stucco is the fact that it is difficult to rectify or repair. Those who live in humid or snowy climates must repair their stucco structures often.
Because stucco is made up of many layers, you will need to have all of those layers repaired, which can be extremely time-consuming and costly.
Different types of Stucco
There are two major kinds of stucco, traditional stucco and synthetic. If you opt for either a classic stucco style or synthetic stucco your home will look stunning.
Both synthetic and traditional stucco has both weaknesses and strengths. We will go over these later in this article.
Traditional Stucco
In contrast to stucco today, which is made of cement, traditional stucco is composed of lime, water, and sand.
A stucco with cement can be beneficial for additional durability. Lime however increases the growth of mold and is the reason it’s not usually a preferred choice.
Sometimes traditional stucco contains acrylics and glass fibers to increase its durability. When using pure cement stucco, it is essential that a solid mesh base must be in place to keep stucco from cracking.
Stucco can last up to 50 years if it is applied with care and maintained properly.
Synthetic Stucco
Synthetic stucco is made of acrylic resin in place of lime and cement. It is also water – and damaged-resistant, giving the stucco an edge over its conventional counterpart.
The process of working with synthetic stucco is easy as it drys evenly and rapidly.
It is possible to put synthetic stucco on foam board, instead of mesh. Nowadays, many construction projects make use of foam board since it is extremely light, waterproof, and simple to cut (simply by using a knife).
The acrylic resin helps the stucco to become more durable, as well as decreases the chance of stucco cracking or breaking.
Is Stucco Simple to Work With?
Stucco is simple to work with, which means you can apply it to concrete walls at your own pace if you’d like.
The wall you are going to apply with stucco must be done carefully to ensure that you get the most durable long-lasting outcomes. Read on as we will show you how it’s done.
It is necessary to apply stucco twice to the concrete wall or in two layers — make sure the wall is free of dirt. Before beginning the DIY project, it is important to review the building code regarding wall construction and requirements for moisture barriers in your local area.
When you’re using stucco to water-resistant walls, you should use two layers of water-vapor permeable Grade D construction paper over the wall’s substrate.
Other things you should consider before you apply your base coat stucco include:
Plywood
Concrete board
Oriented strand board
How to Stucco the Concrete wall – Step by Step Instructions
1. Wall Preparations
It is necessary to make sure that the wall is prepared in two scenarios:
-when the wall has surface contamination and laitances
-when the wall isn’t able to take in any moisture.
Check for any large holes or cracks in the wall. If there is significant damage you should repair it with a layer of skim coating.
Another crucial thing is to cleanse the surface and get rid of any dirt, paint or efflorescence, or other contaminants that could hinder proper bonding.
Most of the time the power washer will be sufficient to remove the contaminants by applying water pressure. In other cases, you may also want to try acid etching to clean the concrete’s surface and make it more porous so that it can allow the stucco to be absorbed better.
2. Apply Bonding Agent
For better bonding, you can apply a layer of bonding agent onto the concrete. This is where choosing the appropriate bonding agent, and mixing it in accordance with the recommendations of the manufacturer is crucial to achieving the best outcome.
Some companies will require at least 24 hours to allow the bonding agent to cure, or decide how many layers or inches you will need to apply. Additionally, the kind of stucco that you apply determines the bonding agent you use. Some do not require any.
It’s best to inquire at the store about what bonding agent would be best for the stucco that you’ve picked.
Another factor to take into consideration is whether you will use stucco in indoor or outdoor applications, both of which require specific kinds of bonding agents.
Bonding agents or adhesive agents can be applied with a spray, brush, or roller, but they should be free of dust and clean.
3. The surface is sprayed with mist
After you have applied the bonding agent and made sure that it’s dry, you should moisten the entire surface with water by spraying over it.
In this way, you can ensure the strength of your bond and stop walls from absorbing the water in stucco, drying it out earlier than it needs to.
Make sure you sprinkle the wall with water, and not douse it.
If you dampen walls, it’s possible to determine how well they will bond to stucco by looking at how it absorbs water. If you observe the water flowing down the wall like you’re pouring water on waxed water, it will not bond effectively.
If you can see that the wall absorbs water, that indicates the bonding will be successful. It’s because it absorbs the water from the stucco and cement particles.
4. Start by making the Stucco Mix
Getting the right mix of sand, water and stucco is essential to creating a flawless surface for the wall. The form and the proportion of materials will be determined by the type of stucco used and the location you choose.
It is important to create a pattern that stays on the trowel while you apply it to the wall. So, you are able to easily move it around and spread it over the surface without applying excessive pressure.
However, it must be strong enough to stick to the surface, and solid enough not to slide as the application is made.
The mixture’s consistency is perfect when your stucco will easily sit at 90 degrees in the trowel.
If your stucco seems too wet, it means that the consistency isn’t right.
Stucco that’s mixed to wet can sink quickly, while stucco that’s dry will not mix well and may take longer to attain the desired consistency. Do not add excessive amounts of water at one time. Instead, sprinkle water as you mix until you achieve the perfect consistency.
Mix your base coat stucco using the wheelbarrow or an enclosed container/medium. This method is simple and is great to use for smaller DIY projects. It requires only just a handful of tools, like hoes, a wheelbarrow, a water hose, and a base coat.
Another method of mixing your base coat is using a bucket and drill. This technique is great for smaller DIY projects. It is ideal if you had a shovel for measuring your cement and sand but this isn’t always simple.
Other tools you require to prepare your stucco with the drill and bucket method:
Mixing drill
2-3 5-gallon (18.9-liter) buckets based on the size of the area that you wish to cover.
Scale
Mixing paddle
Hose for water
Basecoat
Casing Beads
Galvanized expanded metal lath
Woven wire stucco netting
You can use a mixer in preparing the mix. Make use of this method for DIY projects that are either large or medium. With a reliable mixer, you’ll be able to complete larger jobs faster and get extra workers for help, too.
5. Application of Scratch Coat
The first coat that you apply to your concrete walls is called the scratch coat. It acts as a primer to prepare the wall surface ready for your final coating making it more smooth and bond better.
Apply a thin coating, approximately 1/4 ” (6.4mm) or 1/2″ (12mm) with the trowel, then wait till it dries.
Create horizontal grooves that are 1/8″ (3mm) in thickness on your wall using a slotted palette, while keeping it perpendicular to the wall. The scratches will make the next layer stick better.
Be careful not to scratch the surface too hard otherwise the stucco will fall off.
Allow the scratched surface to completely dry over two days, then apply water gently to allow it to cure to prevent shrinkage and cracking. But, you must apply the misting more frequently when you live in an area where water evaporates fast, such as in windy or dry and hot weather.
6. Introduce the Brown Coat
The brown coat can be part of the three-coat stucco method not suitable for concrete. Some contractors suggest this for extra strength in lieu of the two-coat method that’s less expensive.
Another method to apply this brown coating is to wait for between 4 and 5 hours after applying the scratch coat until it is sufficiently rigid to make sure it doesn’t crack.
When you apply the brown coat now, the scratch coat absorbs the water from the brown coat, leading to the formation of a stronger bond.
This technique — referred to as double-back, increases the thickness of the layer and is more porous. It also makes it less susceptible to drying out early.
The problem is knowing when you should add the brown coat. This can be difficult, particularly in colder weather.
Whatever method you decide to use, you should apply the brown coat using a darby, filling each crack or hole and creating an even surface.
By reaching the thickness at 3/4″ (19.05mm), allow it to dry, and then apply a sponge masonry floating to smooth the surface.
Then wait for 48 hours. mist at least once a day, based on weather conditions.
7. Final Layer Application
This is your final, most thin layer, which gives the entire surface a polished, smooth appearance. Mix the final mixture similar to the scratch coat. However, you may add sand or a pigment to create your desired color and appearance.
Spread the mix on the surface with the trowel, and then create a 1/8″ (3mm)-thick layer.
The final texture will depend on your preference: you can smooth it by floating or giving it any texture you like.
Allow a few days for the final coating to dry after which you can moisten and mist the surface as necessary. The curing process can take several weeks, based on the weather conditions.
It is also advisable to keep the stucco away from direct sunlight, as it can cause it to dry out prematurely and alter its color.
Giving the color to your Stucco Wall
The stucco finish coat could be utilized to create decorative color on concrete wall surfaces. There are two color options available in gray and white. You can mix stucco’s finish coat with various standard mortar colors of your choice.
Many textures are possible according to your preferences. It will require some practice to achieve the desired result.
For instance (example of commercial textures):
- Lace and skip
- Cat face
- Dash
- Sand/float
- Smooth
- Worm/swirl or putz
- Santa Barbara
- English
Textures like heavy lace, light lace dash, or sand/float can be stunning and are easy to create when you practice. Apply 1/8 inch (3.175 millimeters) of stucco that is thick for your finish coat, beginning at the bottom of the wall up to the top. Utilize a whisker brush to apply the stucco for the finish coat on the wall.
If you are looking for a more substantial texture, it is necessary to apply stucco’s thin finishing coat uniformly, and ensure you get the color evenly distributed. After you’ve applied the light coat then apply another coat of stucco. This one will be more dense and uneven. After that, you can slash the surface that is getting ready to set using the trowel making a lace effect.
If you would like a smoother texture, apply the trowel or sponge to float in a circular movement on the surface. It is recommended to finish the project with a single application in order to avoid color smudges. You must ensure that the surface remains damp by using fine water mists to keep it moist for a few days.
Different Stucco Finishes
In the past, we’ve discussed the various stucco finishes that you can apply to your concrete walls, based on the style you prefer. Every stucco finish is beautiful however, you must select the one that fits your house best. Let’s look at the different stucco finishes.
Cat Face
This cat-face is perfect for homeowners who prefer large concrete areas that are smooth, and with evenly-placed rough patches. They are also known as inclusions and could vary in size as well as shape.
You can get the cat-face finish using acrylic or traditional synthetic stucco.
Lace and Skip
The most common use for it is on commercial buildings, the skim and lace finish is rough with imperfections that can be easily concealed due to its texture.
It is possible to create this look with your hands or spray it onto the surface and then flatten it using the trowel. You will need two coats to make this appearance, the first being a base coat followed by the texture.
Sand/Float
Typically used in commercial buildings, the sand floating finish is flexible and can be applied to synthetic and traditional stucco in only one coat.
Because it’s fast and easy to make. It is a great choice for your first attempt at DIY stucco. Sand or float is available in three types of finishes: medium, fine and coarse.
Dash
Dash can be sprayed onto houses in medium, light, or even heavy volumes and creates a distinctive style unique to its own.
It’s possible to apply the texture manually if working on smaller areas or with the use of a hopper gun when you’re working on large areas.
Ideal for homeowners who are worried about cracks, the dash can be replaced with 1-3 coats.
Putz or Worm/Swirl
Also called the swirl finish or putz finish, the worm uses a trowel that moves large pieces of stucco aggregate across the surface in order to make indents/scratches across the surface of the stucco.
The finish isn’t as well-known as it was, possibly due to the fact that it’s hard to repair when it’s cracked. However, some modern houses are still using it due to its distinctive texture.
Smooth
If you prefer your walls to have a smooth texture with a smooth surface, then this texture is perfect for you, however, it is also among the most difficult designs to create.
The soft texture is well-known because it is easily colored and matched to a building’s style.
The texture makes it easy for homeowners to choose different shades for their walls to create that “mottled” appearance.
Santa Barbara
Santa Barbara is perfect for those who prefer an adobe-style finish. It can only be used in traditional stucco designs.
Sand particles of fine quality are utilized to create an adobe-like look. It is possible to achieve a stunning smooth surface with this type of texture, however, it’s prone to cracking that is visible.
English Stucco
Although it’s true that the English texture isn’t used as often in contemporary buildings people who want the idea of giving walls the aged appearance will appreciate this texture.
There are still some structures with this pattern, particularly older structures. If you are planning to utilize this texture, make sure you make sure to use stucco that is traditional.
Key Takeaways
Stucco has been utilized for a long time for construction purposes as a covering to protect the exterior of buildings, walls, ceilings as well as sculptural materials used in architecture. It only requires a 2-coat system to stucco concrete walls.
It is essential to make your stucco mix correctly and follow all steps necessary to stucco your concrete wall effectively.