Stucco Installation Tips
Stucco is an attractive, durable, and cost-effective choice for the exterior of a home. It’s also a good choice for renovating older homes or making oversize additions to existing structures.
It’s important to hire Stucco Repair Philadelphia for stucco installation to ensure that the process is done properly. A skilled contractor will help prevent common problems that can lead to expensive repair work down the road, including cracking and bubbling.
The first step in any stucco project is to erect scaffolding that meets OSHA standards and will remain in place for the duration of the project. This will allow the contractors to perform the necessary repairs, remove the old stucco, and apply the new exterior.
Next, the builders will inspect your home’s current structure to make sure there are no cracks or breaks in the sheathing and framing that could cause moisture to seep between the internal walls and the exterior stucco. They will also check for any wood damage, such as rot or mildew, that must be repaired.
Once the building is ready, the installers will hang a layer of building paper to prevent moisture from leaking into the wall system. They will then install a layer of 2.5-gauge galvanized wire lath over the building paper. This layer of lath is the base on which the stucco is applied and provides rigidity. It should be lapped vertically and horizontally with at least one inch of overlap. Corner aids and arch aids are then added to strengthen corners, arches, and curved walls.
The scratch coat is the first layer that is spread onto the metal lath. It is made from a mixture of cement, sand, fiberglass, and acrylic additives. It is applied with a hawk and trowel and must be left to harden for at least 36 hours. This will prepare the surface for the brown coat, which will be used to add strength and thickness. The brown coat is hand-troweled and can be textured or painted in a variety of colors.
Preparing the Substrate
Stucco is a popular choice for exteriors because it is durable, requires little maintenance when professionally installed, and comes in a variety of textures and colors. It also has fire-retardant properties and is mold-resistant. But before stucco can be applied, the underlying surface must be prepared for the process.
This begins with erecting scaffolding that meets OSHA standards and will remain in place throughout the construction process. Then, any deteriorated or damaged wood framing will be repaired, and waterproofing will be added where necessary. The new three-coat stucco system will then be applied to the structure.
During this phase, your contractor may also apply a vapor-permeable weather barrier. These sheets are usually made from asphalt-saturated paper or a manufactured plastic-based material that is a good fit for this application. They are designed to protect the wood framing from rain and vapor while allowing water vapor to escape and vent inside the building.
The first coat, called the scratch coat, is a mixture of sand, cement, and reinforcing fibers. It is applied to the wire lath and scored with shallow, horizontal lines by a notched trowel. This helps the next layer adhere to it better. The scratch coat should be wet-cured by misting or fogging it twice a day.
It is common for cracks to form in new stucco, especially at the corners of windows and doors. These are caused by the normal movement of the building due to changes in temperature and humidity. To help reduce this problem, contractors can add a corner bead to the corners or use a product like Cornerite (TM) to reinforce them.
Applying the base coat
Stucco is a popular choice for home exteriors, especially in warmer climates. It is easy to care for and provides a great deal of protection from the elements. However, it can become dingy over time, and a fresh coat of paint can refresh the look of the entire wall. If you have stucco in your home and want to give it a new coat of paint, here are some tips that will help the process go smoothly.
Before beginning to paint, make sure you have everything you will need in order to work properly and quickly. You will need a bucket for mixing the material, two different buckets to store the mix in between stirring, and a large shovel or scoop for measuring out your sand and cement. You will also need to prepare the area you will be working in by placing drop cloths over furniture that can’t be moved and taping trim.
The first step in the process is to apply the base coat. This is done by troweling a layer over the scratch coat until it is about 3/8 inch thick. Then it is scraped flat with a darby to ensure there are no voids and the surface is smooth. It is then floated with a sponge masonry float and allowed to cure for 48 hours, misting as needed to keep it moist.
This is a vital step in the process. It will serve as both the primary cladding and the substrate for the finish. Poor curing of the base coat can result in failure to perform these functions or even cracking of the underlying sheathing.
Applying the scratch coat
The first coat of plaster that a stucco contractor will apply to your wall is known as the “scratch coat.” It’s a mixture of sand and cement that’s applied to the lath. It’s important to make sure that the scratch coat is applied properly so that it adheres well to the base of the wall.
The mix for the scratch coat typically consists of 3 parts sand to 1 part cement. The ingredients should be well mixed so that the consistency is smooth and won’t sag when you hold a trowel upright. Some people prefer to add lime and other materials to the mix for their personal preference, but it’s not required for the stucco application process.
Before applying the scratch coat, the wall should be cleaned and washed using a power washer or scrubbed down with trisodium phosphate (TSP). Once the wall is clean, it should be wiped down and then thoroughly wetted. It’s also a good idea to install corner and arch supports at this point. These are stronger pieces of wire that help strengthen corners, arches, and curved areas in the walls.
It’s important to choose a tape that is designed for stucco work. This type of tape is more resilient and able to withstand the weight of the plaster and the movement caused by changing temperatures. It must be able to stay intact on the surface of the wall for 7, 10, or even 60 days, and it must be easy to remove cleanly when the job is done.
Applying the Brown Coat
The brown coat is a thick layer of a mixture that looks more like cement than plaster. It can be troweled directly onto the scratch coat, or it can be sprayed. It is important to allow time for the brown coat to cure before applying polyprep or color. Consult with your contractor or brown coat manufacturer for specific cure times.
When using a two-coat system, the brown coat is usually not scarified or scored (except at architectural details). It is a structural layer that adds strength to the lamina. It can also be used to provide a decorative surface for the finish coat.
A good brown coat provides an even thickness over the whole wall. The plasterer trowels the material to a depth of 3/8 inch, then scrapes it flat with a darby and fills any voids for a smooth, even surface.
Some stucco contractors use a one-coat system that is mixed with Portland cement, sand, and fibers to speed up the three-coat process. This product can be applied over framed walls, including OSB and gypsum sheathing, as well as concrete and brick walls. It is a good idea to check with your contractor or the manufacturer to see if they recommend the use of this product over frame construction. Regardless of whether you are using a traditional three-coat or one-coat stucco system, you should always follow the rules for joint spacing as specified by the manufacturer.
Applying the Finish Coat
The application of the finish coat gives the stucco its final texture and color. The finish coating also protects the stucco from blunt damage and provides waterproofing. Reputable stucco contractors use an acrylic finish that comes in a variety of colors and textures to enhance the look of your home’s exterior.
A good stucco mixture is a combination of Portland cement, sand, and water, with lime or plasticizer added for workability. It must have excellent tensile strength, freeze-thaw durability, and bond well to the lath or substrate. It must also be easy to trowel and resist sagging. In addition, it must be free of sulfates and other contaminants that cause corrosion.
In addition to the standard expanded metal lath fastened with nails or galvanized staples, rebar and/or fiberglass netting are often added to support and strengthen walls. It is important to properly install these reinforcement materials in order to avoid movement cracks that are caused by the expansion and contraction of the building. Corners, arches, and curved walls are especially susceptible to cracking, so installers use a special corner bead and/or additional reinforcing wire in these areas.
The three-coat stucco process requires a great deal of skill, experience, and time to get done right. It is not a do-it-yourself project, and any mistakes will cost you in terms of both time and money. Choosing a reputable contractor will ensure that your project is completed in a timely manner with high-quality workmanship and an attractive result that will last for years to come.