How to stucco is not a big secret, nor is it rocket science. Knowing the process of mixing stucco and how to apply stucco are mandatory for a successful stucco job. One of the major secrets to applying stucco is mixing stucco so every batch has the same perfect consistency. If you can do this, the crew with the trowels in their hands will have an easier job of applying stucco.
When applying stucco, match your mixing system to your stucco application system. Then there is less waiting, less hardening of the stucco in the mixer, wheel barrows, and stucco sprayer. In short, the operation runs smoothly. If the crew knows how to apply stucco and they are using the Tirolessa USA Mortar Sprayer, they can apply 60 cubic feet of stucco per hour That is 1,440 square feet at one half inch thick per hour. That is enough stucco to keep a crew of 4 busy mixing with a two-bag mixer and wheel barrowing to the spray crew. When they break for lunch or at the end of the day, the cleanup is minimal.
Some people use a one-bag mixer and load it brim full with two bags of stucco. This slows the mixing action. Crews who know how to stucco recognize that the mixer should be only 60% to 80% full to provide optimum mixing action. If it is fuller, the stucco is not fully mixed, clumps may interfere with applying stucco, and worse, any water reducing agents or plasticizers may not be fully activated. Many two-bag mixers come with a 5 to 8 horsepower gasoline engine.
Most stucco requires one cubic foot of cement materials (Portland cement, blended hydraulic cement, masonry cement, plastic cement, hydrated lime, fly ash etc.), three cubic feet of plaster sand (coarser than masonry sand), and from four to seven gallons of water. Depending on the formula, admixtures may be needed. For example, Portland cement, sand, and water do not have the body to allow it to stick on a wall. The mix either needs hydrated lime added to it or needs a chemical plasticizer.
Cement comes in one-cubic-foot bags. Masonry cement usually ranges from 70 to 78 pounds. Plastic or stucco cement usually is 80 or 94 pounds. Portland or blended hydraulic cement is usually 94 pounds. Some companies make half-bags of cement. A 47-pound bag of Portland cement is not a cubic foot, but a half-cubic-foot. Lime is usually packaged in 1.25 cubic foot bags which weigh 50 pounds.
Three cubic feet of loose, damp sand contains about 240 pounds of dry sand and will fill four 5-gallon buckets level-full.
How To Stucco Video:
With the first batch of stucco to be mixed, you will not know the amount of water that will be required. If the stucco is made too wet, it is often easier to throw the batch away rather than to try to salvage it. Even though you have a two-bag mixer, your first batch should use one bag of cement. Here are the steps to follow:
- Fill one bucket with water to about 1.25 inches from the top (this is 5 gallons). Fill a second bucket half full (this is about 2.5 gallons).
- Clean out the mixer, including chipping off loose material.
- Lock the mixer drum in the upright position.
- Start the mixer, put it in gear, and speed the engine up to a very rapid idle.
- Add about 3.5 gallons of water from the fuller bucket. Ensure that your helper does not refill the bucket as it is set down.
- Add 2 buckets of sand.
- Break the cement down into two buckets. Add one of the buckets slowly.
- If the stucco mix remains soupy, proceed with adding the remainder of the cement. If the mix becomes stiff, add additional water and then add the second bucket of cement.
- After all of the water is added, the mix should have the consistency of toothpaste.
- Mix until there are no lumps remaining.
- Add the remaining sand. As the sand is added, the mix will become stiffer. Add additional water as needed to maintain a mix that rolls freely off the mixer blades.
- When the stucco mix appears correct, take the mixer out of gear and reach into the mixer with a long-handled cup (If you are going to put your hand into the mixer with the mixer running and in neutral, please buy extra insurance before you do so and have it assigned to me.) and obtain a sample. If you do not have a long-handled cup, pour a small amount of stucco into a wheel barrow.
- Place a full cup of stucco on a steel plastering trowel and tip the trowel. If the mix slides off before the trowel is at a 40 degree angle, it is probably too wet.
- Apply the stucco to the substrate that you are applying stucco to. If it sticks well, it is a good consistency. If it peels away when the trowel is removed, it is probably too wet or too dry. Adjust the water and retest. If it appears to adhere well, but the edges of the application pick up a little bit, it needs slightly more water.
Please visit our stucco mix design page for more stucco recipes.
Determine the amount of water that was used for the one-bag mix. In the future, add 75% of this amount of water to the mixer if making a 1-bag mix or 150% of that amount if making a 2-bag mix.
Dump the contents of the mixer into wheelbarrows. Add the water for the next batch, and let the mixer run until you start mixing the next batch. This keeps the stucco from hardening in the mixer.
The second and later batches are much easier to mix if you measure the sand and water for the next batch while the previous batch is mixing. With the mixer running:
- Add 75% of the water needed.
- Add half of the sand.
- Add cement.
- Add remaining sand and remaining water.
- Mix for 4 minutes after all components are in the mixer.
The crew applying the stucco should report to the mixing crew with recommendations for adjusting the water and the sand concentrations.
If you have more How to stucco or mixing questions, please contact Nolan for help and advice.
Stucco Application on a Fence
The photo above shows stucco application on a 130 foot long stucco fence. Pamela Volkmar is spraying stucco, while a crew is mixing to keep up with her. According to Rodney Volkmar, the stucco sprayer can keep 2 mixers going and 5 men troweling behind it. This 130 foot fence was completely covered with the first coat in six hours. For the fastest coverage, Rodney finds that premixed, bagged stucco is the easiest way to keep up with the spraying and the mix is consistent.
The Kinch Family Replastering Their Pool for $502
Richard Kinch has shared a great story about re-plastering his pool with his family at a fraction of the cost of hiring professionals. The job is complete and the pool is ready to be filled. Visit Richard’s website to see the many details involved with this pool replastering project.
To learn more on How to stucco, Go to the Stucco Information page.