Stucco is energy-efficient and adds excellent insulation to a home. It is long-lasting if properly maintained, but it’s important to assess its condition regularly.
The modern stucco process involves 14 steps, including lathing, scratch coat, brown coat, and finish coat. It also includes internal protection and exterior waterproofing. Contact Dryvit Stucco Installation now!
Stucco requires a strong substrate that is moisture-resistant and will support the application of several layers of stucco. The substrate may be a masonry surface such as brick, stone or concrete or wood framing. When installed over a masonry surface, the stucco is applied directly, without lath, to obtain an adequate “key.” On a wood structure, the stucco is typically placed over horizontal wood lath or metal sheathing attached to vertical wood furring strips.
The sheathing may be a plywood sheathing, exterior insulation board (EIFS), expanded polystyrene foam (EPS) or extruded polystyrene foam (XPS). A layer of vapor barrier is normally installed to prevent moisture infiltration. A layer of fiberglass mesh is also often embedded in the base coat to add reinforcement and resistance to movement cracking.
Before stucco is installed, scaffolding is erected for safety and to provide a stable platform to work on. In addition, the substrate is examined for damage and deterioration. It is important to repair any underlying damage and to ensure that it is moisture-resistant.
The first step in the stucco process is applying an initial layer of mortar to the building’s exterior. This initial layer is called the “scratch coat.” This scratch coat is a mixture of Portland cement, lime powder, sand and water. It is sprayed on the wall using a notched trowel. A brown coat is then sprayed over the scratch coat to level the surface and establish an even foundation for the final coating.
It is important that the mortar mix not be over-mixed. This will cause the mortar to set too quickly and prevent proper bonding with the lath or masonry substrate. The mortar should be mixed for one-and-a-half to two hours before application to allow for proper mixing and curing. If the mortar is not mixed properly, it can develop crazing and discoloration as it sets. Also, the time of year that your project is completed will affect how long it takes for the stucco to cure. Fall and winter are not the best times to install stucco because rain, snow or cold weather can delay the drying process.
Preparation
Stucco application requires expert timing and proper preparation to create a durable finish that protects against moisture and withstands time. This stage involves several meticulous steps, including cleaning the surface and addressing any cracks or damage. It also includes installing trim accessories, such as weep screeds and casing beads, to ensure that water can escape the walls. Weep screeds are placed along the bottom edge of the wall and secured with galvanized nails or screws. Casing beads are applied around windows and doors, creating clean, even edges and corners.
The next step is to make sure that the underlying sheathing and framing are in good condition. It is important to repair any damaged areas before applying new stucco, as the integrity of the sheathing can be compromised if it isn’t repaired properly. It is also a good idea to install weather stripping, which helps keep cold air out during the winter and hot air out during the summer.
Lastly, it is a good idea to remove any old or damaged plaster and wood lath. This can be a messy process, so it is important to have a good quality mask and work gloves when performing this task. The next step is to prepare the metal lath for stucco by applying a scratch coat, which is a mixture of sand and cement that is applied in lines on the bare metal lath. This step is critical, as it ensures that the brown coat and the rest of the stucco process adhere correctly to the wall.
Once the scratch coat has been allowed to cure, the brown coat can be applied. This is a thicker mixture that is applied with a trowel and pressed firmly into the metal lath. It is important to apply a thick layer and to press firmly to avoid any gaps or uneven areas. The brown coat should also be left to cure before the next step is taken.
During the final phase of the stucco application, the installer can choose to add texture or a pattern to the surface using different tools. This gives the stucco a unique appearance that can really set it apart from other homes in the neighborhood. The stucco can be painted or stained once it is completely dry, which will help protect the material from moisture and other environmental factors.
Application
The stucco process is an intricate one and is better left to the professionals. A reputable business is insured and will guarantee their work, giving homeowners peace of mind that the job will be done correctly the first time. They will also know what is required in order to pass any inspections by local code enforcement.
Scaffolding will be erected around the building to provide a safe working platform. This will be used for removing any old stucco, repairing underlying damage and applying the new exterior system. This scaffolding will be a requirement even for small jobs because the heights involved in this type of work can be dangerous for non-experienced contractors or homeowners.
To begin the application, a scratch coat is applied to the wall. This is a mixture of sand and cement that will serve as the base for the brown and finish coats of the stucco. After the scratch coat has been allowed to cure, the brown coat is applied. This layer is composed of a mix of 1 part cement materials and 1 1/2 to 3 parts sand and may include pigment for added color. After the brown coat has been troweled and floated, it will require 36 hours to dry completely before adding the finish coat of stucco.
The finishing stucco can be a smooth, textured or decorative in nature. Once the finishing stucco is installed, any necessary expansion joints will be installed. These are installed to relieve the stresses caused by rising and falling temperatures that can cause the different components of a building to expand and contract at different rates. Corner trim will also be installed to create a finished look for the corners of the wall.
Wood-frame homes that are being built per code will need to have a vapor-permeable weather barrier installed. This is usually a cement-based primer or a manufactured product such as one of the various plastic-based house wraps that are available on the market. These products have proven to be insufficient in protecting sheathing from moisture damage when compared to two layers of Grade D building paper and flashing.
Finish
Stucco is a popular exterior finish for homes because it is versatile and offers a variety of design expressions. It is durable, fire resistant, and easy to clean. However, it is not maintenance-free and requires frequent inspection and repair of cracks. It is also not effective in wet climates because moisture breaks down the stucco, and moisture seepage can damage the walls of your home and compromise its structural integrity.
The stucco process has three main steps: lathing, scratch coat, and brown coat. Lathing involves the insertion of wood, metal, or plastic lath into which plaster is applied. The scratch coat is a mixture of sand and cement that is applied in lines to the surface and left to cure. This layer is a key part of the stucco process, as it provides a rough surface that helps ensure the brown coat adheres well.
After the scratch coat is cured, the brown coat is applied. This is a thicker, more robust mix of sand and cement that serves as a strengthening layer. This layer is usually hand-troweled and may be textured or smooth. It is sometimes tinted with pigment before application to add color to the stucco.
Once the brown coat is dried, the finishing touches are added. Corner trim is used to create a clean and finished look around the perimeter of the wall. Flashing is installed along the bottom of the wall to keep water from leaking in between the stucco and substrate.
A rain screen is installed over the WRB, as well as E-Z beads around window and door frames to help with air circulation, preventing mold and other problems from growing within your home. Expansion joints are placed at the corners and where the substrate changes, allowing for the natural expansion and contraction of the wall panels as the temperature fluctuates.
While some people attempt to do-it-yourself, a professional stucco contractor is the best way to get your project done right. Reputable businesses provide reasonable pricing and a warranty for their work to give homeowners peace of mind. If you are thinking about installing a stucco exterior to your home, contact a local stucco company today to learn more about their services.