How Stucco Works

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Have you ever wondered how stucco works? The traditional style of applying it to a building follows a specific process. It is not as simple as adding one material to the structure's walls. Instead, there are three major layers involved. We explore each of these layers and their application below.


Scratch Coat

The first layer placed onto your building is the scratch coat. This muddy material must be mixed to the right consistency or brings problems of its own. Mixing too much water will make the mud slip and slide instead of staying in place. Stiff material does not spread evenly as it should and leaves an unattractive pattern. The trick is in mixing small amounts of the mud at a time to ensure you create the right consistency.


This first coat, called the scratch coat, is one of the easier layers to create. But the workers must ensure it is level and even as they apply it over the metal lath on the home's exterior sheathing. It also requires quick action with a screed, also called a slicker, to flatten the layer out. Finally, they fill in voids and reduce peaks for optimum smoothness.


Anyone who has ever attempted to work with this material knows the process is trickier than it looks. That is why it is best left to the professionals with experience.


After creating a level surface on the wall, the workers must scratch horizontal lines in this layer. This scratching helps the next layer, the brown coat, bond appropriately.


Brown Coat

The brown coat work does not start until the previously applied scratch coat has set overnight. Workers first wet down the wall using a water hose. They mix new mud for some difficult layering over the scratch mud. The process involves paying close attention to the coats' level and smoothness.


The brown coat is also a fast process that can appear furious. The workers must work quickly to smoothly apply this layer. Then, they must use the slicker before the mud dries. During this application, they keep the scratch coat from drying out by dousing it with the hose. This work can require multiple people if the conditions are right for quickly drying the mud.


As with the scratch layer, the brown coat must be made flat and smooth. Then it must rest overnight before application of the finish coat.


Finish Coat

The finish coat is aptly named because it is, indeed, the last layer. It is also the only layer that people see. This is where some artistry takes place in the hand troweling and texturizing of the coating to make the finish appealing. Professional stucco contractors have a variety of finishes they can apply to provide the appearance you want.


Find the Right Pros for Your Home's Stucco Finish

People who work in this field typically specialize in stuccoing and acquire extensive experience. The craft appears to involve basic mud-slinging. But it is actually a lot more involved. It is important to not underestimate how much work this type of project takes.


Obviously, it is best to hire an experienced contractor. You can certainly try to do a small job, yourself. But beyond adding a mud finish to a small out-building or backyard shed, it is typically best to enlist the pros.

Done well, your building's exterior can last 50 to 80 years. Even with such a lengthy life expectancy, this surface material requires less of an annual investment for maintenance than virtually any other type of exterior siding. General maintenance includes routine cleaning, sealing and repair of cracks and other issues.


Comments (2)

Richard Weeks
Dallas, TX
REALTOR®, Broker

Great information thanks for sharing.  I hope you have a great day.

Apr 02, 2021 02:23 AM
Robert Sole
REM Inspections LLC - Winter Springs, FL

You are absolutely correct in how it is supposed to be done.  The contractors that did it that way were true artists.  Unfortunately, you will have a hard time finding it done that way now in new construction.  These days, it is usually done in one coat and the texture is sprayed on with a hopper.   It is definately an inferior finish.

Apr 02, 2021 12:01 PM

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