How and how to properly plaster polystyrene foam outside the house with your own hands

Enhancing insulation and shielding the material from the weather can be achieved by plastering polystyrene foam onto the outside of your home. Even though it could seem like a difficult task, you can do it yourself and get professional results if you have the right resources and advice.

We’ll guide you through the processes of priming the surface, selecting the appropriate supplies, and plastering over it in this article. Plastering polystyrene foam can be a satisfying do-it-yourself project, whether your goal is to increase energy efficiency or just give your house a new look.

We’ll go over everything, from plaster mixing to finishing methods, to make sure you have all the knowledge required to finish the project successfully. Let’s begin the process of giving the outside of your house a smooth, long-lasting plaster finish.

What type of foam is suitable for plastering?

The synthetic polymer polystyrene foam, whose name is conveniently shortened to three letters, is the basis for the building material. The majority of the insulation is made up of gas. Low weight and excellent thermal insulation are its features.

• low thermal conductivity, due to which the heat remains inside the room;
• good sound insulation;
• Light weight – it is easy to transport and mount to the walls;
• resistance to fungal diseases, decay and corrosive processes;
• Environmental friendliness – material does not distinguish between substances harmful to the environment;
• affordable price.

• low vapor permeability;
• Small strength – the insulation is destroyed under the influence of moisture and sunlight;
• Flame fraud.

Furthermore, mice, bees, wasps, and other insects frequently begin their lives in the froth.

Adding polystyrene foam to your home’s exterior is a sensible approach to improve insulation and weather resistance. This post will walk you through the necessary actions and supplies to complete the task yourself, guaranteeing a beautiful and long-lasting finish. You don’t need to hire a contractor to get professional results if you use the right tools and techniques.

Is it possible to plaster polystyrene, and why it is done

The plaster decoration process that follows is implied by the foam facade insulation technology. Experts claim that this is the best option because it adds a layer that protects the insulation from moisture, UV rays, and other unfavorable weather conditions while also extending its service life.

• the finishing layer creates barriers for sunlight, which have a destructive effect on polystyrene foam;
• in combination with a reinforcing coating, it protects against mechanical damage;
• does not allow moisture to pass through;
• creates additional sound insulation;
• reduces the risk of fire;
• plaster prevents insect invasion.

It is important to keep in mind that the finishing material’s foundation determines the task completion percentage.

What to plaster polystyrene foam with

It is advised by construction experts to prioritize mixtures that are resilient and persistent.

Interior work is appropriate for any composition. If you are unsure about how to plaster polystyrene foam outside of your home, you should select a facade-specific solution. Gypsum mortar is not appropriate for outdoor work due to technical reasons, and cement breaks down the insulation’s structure.

— the priciest kind of plaster, which retains its color and texture in the sun and is extremely strong, elastic, and durable. It can also be used to remove excess moisture without losing heat.

Distinct from decorative plaster, foam plastic plaster is available as pre-made, specialty mixtures. Manufacturers consider the material’s adhesive qualities, strength, and durability. As a result, additives that increase adherence to polystyrene foam are included in solutions sold under the Ceresit, Ecomix, and Stolit brands.

• for gluing insulation to walls;
• to create a protective layer;
• universal.

Any point during the project can make use of the most recent iteration of the solution. The only recommendation is to select a mixture from a single manufacturer.

Features of plaster for foam plastic

If you use a reinforcing mesh as a finishing layer, foam plaster will last longer. Prior to applying the solution, the insulation is not primed. The primary characteristic of polystyrene foam is that the dew point, or the temperature at which condensation first forms, is found inside the skin, where cold air does not exist. As a result, heat builds up and the building cools more slowly.

According to the facade

In the event that you choose to use foamed sheets for insulation, experts advise implementing the "wet facade" technology.

• a facade primer for plaster is applied;
• glue solution;
• insulation;
• reinforcing mesh;
• leveling finishing layer;
• primer;
• final coating.

Indoor decoration

You can entice the room from the inside if you are unable to reach the exterior wall. The walls are prepared in the same way with external insulation for interior work. Next, mount the mesh, adhere the foam, and use the solution. The final coating, t.To, is the only area that differs. Walls can be covered with wallpaper or decorated with plaster. After that, putty is applied to the leveling layer once more, and it is dried.

DIY plastering technology

• the walls are primed and leveled;
• a sheet of polystyrene foam is attached to the adhesive solution;
• a reinforcing mesh is installed;
• a base finishing layer is applied to smooth out unevenness;
• finishing solution.

Tools and materials for work

• primer for leveling the wall;
• adhesive solution for foam plastic;
• insulation;
• plaster for leveling and finishing layers;
• reinforcing mesh;
• roller;
• plastic corners;
• mixer;
• emery grater;
• dowels;
• putty knife;
• trowel.

For plaster, any foam plastic will work, but it’s best to buy the entire solution right away from one supplier.

Mixing

The manufacturer will typically specify the preparation method and proportions on the packaging. The instant work begins, the solution is ready.

• Pour cold water into a container;
• Add powdered material;
• Mix with a mixer until a homogeneous mass is formed;
• Cover with film and leave for 10-15 minutes;
• Mix again.

Preparing the base of the facade for plastering

Upon completion of the foam plastic installation, the treated surface must be thoroughly inspected. There should be no flaws in it. Polyurethane foam is used to fill in the seams. Using a knife to scrape off any leftover glue and sandpaper the joints are required steps. Builders frequently employ a trick whereby, if the foam sheet is perfectly smooth, they apply sandpaper or a specialized roller to it. A process like this will guarantee a more robust adherence to the solution.

Closing the seams of the house with foam plastic and plaster

It is imperative that the building’s seams remain unoccupied to prevent the buildup of cold air. Foam is used to treat them. The filler is carefully cut off if it gets onto the foam.

Selection and fastening of the reinforcing mesh on the foam

The goal of the reinforcement is to coat the insulation system uniformly and solidly. Builders advise using fiberglass mesh for insulation work because it can withstand alkaline environments. The ideal material is thought to have a density between 40 and 160 g/m². It quickly assumes the necessary shape and strengthens the foam’s adhesive qualities. The leveling layer needs to be primed. It guarantees improved finishing adhesion with earlier coatings.

After the insulation is finished, if painting the walls, a waterproof paint solution is used; if applying decorative plaster, the primer used for the plaster application needs to include quartz filler.

• The first layer of plaster is applied to the foam, its thickness should not exceed 2 mm;
• the mesh is laid with an overlap, with an overlap of 5-10 cm (on slopes near windows and on doorways it is fixed with corners);
• the next layer is applied when the first one is completely dry, its thickness should be 3-4 mm.

With the use of this technology, the uneven material can finally be smoothed out and the plaster applied to the insulation fixed.

Facade grouting of the surface

An emery float or grinding bar is used to give the reinforcing layer a smooth surface. They assist in getting rid of every flaw that was impossible to conceal in the earlier stages. The first instrument is a plastic float that has an emery cloth fastened to it. It is possible to swap out the skins while working.

• for textured decorative plaster – coarse-grained attachments;
• for painting – fine-grained.

Once it has dried completely, surface processing can start. It takes two to four weeks to complete. After that, you have to do as instructed to avoid damaging the reinforcing layer. When the sanding tool is firmly pressed against the wall, strong counterclockwise circular motions start. To keep the layer even throughout the process, the pressure should be roughly the same at every stage.

No need to spend a lot of time in one place. The strength of the surface being treated will require multiple sandpaper changes. Use a brush or broom to remove any remaining dust from the walls when the job is finished.

Final alignment on the façade

There is a small variation from the standard procedure in the way the finishing layer solution is prepared. The mixture is made more liquid for these reasons, allowing it to slide off the spatula with ease. Apply to the wall using a wide-tipped tool. The finishing coating should have a thickness of 3–4 mm.

• knead the solution in small portions (so as not to freeze);
• the surface is mentally divided into equal squares;
• process it gradually, in small sections.

Preparation before applying the decorative layer for the facade

The wall is left for another day until the plaster dries after the work is finished. Use a sanding bar to go over it once more after that. The surface needs to be cleared of dust before priming can start. A roller is used to apply the solution, and a paintbrush is used to handle corners, slopes, and other difficult-to-reach areas. Applying the primer mixture in two layers will strengthen the finishing material. They all take between 20 and 24 hours to dry.

The next design option determines the finish coating thickness. Paints that may harm the foam, for instance, should not be applied in thin layers. It can be covered with textured plaster or covered with wallpaper.

Applying decorative plaster to the cladding

Decorative plaster decorating can begin after the primer has dried. The mixture is made in accordance with the directions provided on the packaging by the manufacturer. The dry composition must typically be mixed with water in the exact amounts. Using a wide spatula and cautious movements from the bottom up, the material is applied to the surface, leveling the thickness of the layer across the wall. Shake any extra solution back into the container. The major goal is to apply a coating that is homogeneous and free of joints and strokes. It is advised to process the entire area at once for this.

The thickness of the layer is typically the same as the diameter of the plaster filler grains. The solution packaging contains information about these values. The mixture is spread out in big squares or vertical lines. They start to form a texture or pattern when they cover the entire wall. Use a sponge, special stencils, a smaller spatula, or a brush for these purposes. Here, it’s crucial to apply the same design to every surface.

Plastering doorways and slopes

After determining the best way to plaster the foam, you must proceed to completing the doorways and the inclines that are close to the window frames. Once the foam has solidified, you can get to work. To achieve the most even area, the excess is chopped off. After that, the process is like laying drywall. Polystyrene foam sheets are cut into the necessary size pieces, which are then mounted around the door or window’s perimeter. Using tile adhesive as a fastener is not advised. Dowels are used to secure the parts after they have dried.

Additional work is completed on the slopes in accordance with the previously mentioned guidelines. The reinforcing mesh is sliced into the proper lengths, covered in a second layer of plaster, primed, and decorated after the corners are secured with mortar. Building materials are sealed with masking tape to keep them from discoloring the glass.

Consumption of facade plaster for external work on foam

The composition of the chosen mixture and the wall processing technique determine how much material is used. For instance, you’ll need 10 kg of universal solution for every square meter when installing external insulation. You will need 4 kg of adhesive mixture and 6 kg of leveling mixture if different types of plaster are used. Plastering takes up the remaining space after applying 3–4 kg of glue foam per square meter when using a polymer composition.

An online calculator will be useful in accurately calculating the consumption of building materials. There is very little program error. It will assist you in figuring out how much plaster is needed without going over budget.

It is advisable to buy a few kilograms in advance because the solution needs to be applied in its entirety at once, as you should keep in mind. Insufficient mixture will cause joints to stay on the finished surface, which will eventually cause cracks. The technical characteristics and quality of identical plasters made by different manufacturers can vary greatly. As a result, they cannot be combined on the spot. Purchasing the entire volume of content under a single brand is advised.

Steps	Description
1. Prepare the surface	Clean the polystyrene foam and make sure it"s dry. If needed, sand lightly to smooth any rough areas.
2. Apply primer	Use a primer suitable for foam to help the plaster adhere better. Let it dry completely.
3. Add a reinforcing mesh	Place a fiberglass mesh over the foam. This helps prevent cracking and increases durability.
4. Mix the plaster	Follow the instructions on the plaster package. Mix until you get a smooth, thick consistency.
5. Apply the base coat	Spread the plaster evenly over the mesh using

Adding a polished finish and better insulation to the outside of your house can be achieved by plastering polystyrene foam. If you have the necessary supplies and are ready, you can complete the task on your own. A long-lasting and appealing outcome can be obtained by following the instructions we’ve provided, which cover everything from surface preparation to base coat application and finishing touches.

Don’t forget to utilize the proper equipment and supplies, such as fiberglass mesh, premium adhesive, and an appropriate finishing coat. These elements guarantee good plaster adhesion while also providing weather resistance. For the best results, take your time and focus on small details like evenness and smoothness with each step.

Finally, even though the procedure could initially seem a little overwhelming, it is doable with care and patience. You will save money and feel good about a job well done if you put in the time and effort. You’ll also improve your home’s aesthetics and energy efficiency. Cheers to plastering!

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