How to plaster foam

Although plastering foam surfaces can be challenging, it’s an essential step to achieve a smooth, long-lasting finish. Foam is frequently used in construction as a lightweight building material or for insulation, but plaster must be carefully prepared for the porous surface of the foam before using it.

You’ll need to take certain actions to guarantee that the plaster adheres properly and doesn’t peel or crack over time if you want the best results. Plastering entails selecting the appropriate kind, prepping the foam surface, and layering the plaster on.

Plastering foam, when applied properly, can provide a sturdy, visually appealing surface that is prepared for painting or additional finishing.

What role does plaster play

Because of several of its qualities, plaster is a tried-and-true finishing material that has become more and more popular.

Plastering over foam serves the following purposes:

• Protects foam from mechanical damage. Probably everyone knows that foam is a very fragile material: as soon as you lean on it, a dent immediately appears. And if you hit it, you will get a hole. Thus, the plaster will be an additional outer layer, a barrier that can protect the foam from numerous damages.
• Protects insulation from harmful ultraviolet rays. Ultraviolet radiation is a serious problem for polystyrene foam. A layer of plaster hides the material underneath, thereby preventing ultraviolet radiation from reaching its surface.
• Provides fire safety. Polystyrene foam belongs to the class of flammable materials, while plaster, on the contrary, is not subject to combustion. In this case, the plaster will act as a shield, a barrier in the path of fire, preventing its penetration, causing the polystyrene foam to ignite.
• Protects from moisture. Although polystyrene foam has a low degree of moisture absorption, if the insulation suddenly gets very wet, it will take quite a long time to dry. Constantly high humidity and dampness around lead to the material losing some of its properties, making it even more fragile and brittle.
• Brings gloss to the walls, giving them a presentable, aesthetic appearance. With the help of plaster, the surface becomes perfectly smooth.

Applying plaster yourself

You can learn how to plaster polystyrene foam correctly by watching this video. Because the coating is inexpensive, it is frequently utilized. Every task is completed in phases, which must be kept in the order they are completed.

Be aware that doing it yourself or using mixtures from reputable manufacturers is preferable. This will ensure that the coating lasts a long time.

Collecting material and tools

If you have the required tools, you can apply decorative bark beetle plaster on polystyrene foam and any other material. He’ll assist you in completing everything quickly.

• Container for mixing the solution;
• Grid;
• Spatula;
• Plaster mesh;
• Drill with attachment;
• Emery cloth;
• Plastic grater;
• Roller;
• A large-pored sponge or grater with a special cloth to create texture;
• Dry plaster mixture;
• Primer;
• Decorative plaster.

This is a comprehensive list of everything needed to complete plastering tasks.

Preparing the surface for work

The prepared surface is plastered using polystyrene foam that can be done at home. This will guarantee the coating’s longevity and quality.

The evenness of walls finished with polystyrene foam sets them apart, necessitating no additional leveling or smoothing. However, it is important to consider the following points:

• Seams. There may be unfinished areas. Joints that are not tightly adjacent to each other, the gaps between them must be well leveled, filled with mortar and given time to dry.
• If foam is found to be coming out on the surface, excess material should be removed.
• The entire work surface is cleaned of dirt and dust.
• Creating better adhesion. Since the surface of the polystyrene foam is very smooth, the glue does not adhere well to it, spreads, rolls off. To eliminate this drawback, you can use a needle roller, rolling it from top to bottom, or use a hacksaw, leaving shallow cuts. Thanks to this, we will no longer get a smooth, but a porous surface. The solution, the glue will be retained in the pores, dry there, providing reliable fastening of the material.

Mix the solution

There is only one answer to the common question of whether warm plaster or polystyrene foam is superior: polystyrene foam will, of course, offer the room greater thermal insulation. Producers create a large variety of ready-made and dry plaster mixes.

There is a unique combination available for every kind of finishing or construction material. Consequently, selecting an appropriate solution won’t be tough; just pay close attention to the packaging.

Polystyrene foam plaster, on the other hand, comes in various varieties:

• Universal, used to perform any operations;
• Special, for gluing polystyrene foam to the base;
• Forming a protective layer.

The ideal choice for these purposes will be a universal mixture because we will be plastering polystyrene foam using a mesh.

Pay attention: buy the necessary quantity of one manufacturer’s, one brand’s mixture for work. Every brand has unique methods for mixing solutions, applying paint to walls, and other processes that, when combined, can produce unexpected results and lower the caliber of the completed project.

• When preparing the solution, follow the manufacturer"s recommendations. Everyone has instructions.
• In general, it is convenient to work with a solution of medium thickness, similar to sour cream. When mixing a large volume of the mixture, use a drill with a special attachment. Please note: mix the solution for one working cycle, for the time during which you will have time to completely use it up. The diluted mixture thickens over time, dries out, i. e. loses its properties.
• On average, when plastering with a mesh, 4 kg per sq. m is consumed.

Laying the mesh for plaster

During the plastering process, the mesh serves to firmly anchor the material to the polystyrene foam surface.

• In this case, it is preferable to choose a material intended for facade work. In this case, one of the important indicators is density. A denser mesh ensures the evenness of the plaster layer. But at the same time, excessive density complicates the process of gluing in the corners. Optimum density is 140-160 g per sq. m.
• Another indicator that is worth looking at when choosing a material is resistance to alkaline substances, since cement is often one of the components in the plaster mixture.

Now let’s get the mesh laid out:

• First, we glue the mesh to difficult places: corner, slope, opening. To do this, cut off a strip, the width of which will be 30 cm, and the length will correspond to the length of the slope. The corner of the wall can be pasted over using meter-long pieces.
• Bend the strip in half, applying force. We press the fold line well so that it is even noticeable when straightening the strip.
• Apply plaster to the wall using a spatula. The layer thickness should be at least 3 mm.
• Apply the mesh to the corner and press with a spatula. Then perform smoothing movements in the direction from the corner to the side and down. Glue the mesh with an overlap, so leave an unpasted 3 cm strip at the edge.
• Repeat these steps to process all corners and slopes.
• Proceed to pasting the rest of the area.
• Cut the mesh into strips. If the room is small, then cut pieces equal to the height of the room. If the surface to be processed is large, then use meter-long pieces.
• Take a spatula and apply the mixture to the wall, making a strip equal in length to the cut piece of mesh, and add an additional 3 cm in width for overlap. Layer thickness – 3 mm.
• Apply the mesh and smooth with a spatula. It should be hidden with mortar, if not – apply a little more mixture. We move the spatula in two directions: from the middle to the edge and from top to bottom.
• When gluing the mesh, leave both edges free so that they can be glued at the same time later. When applying the edges one by one, after plastering, a rough, protruding joint is obtained. It will be very difficult to hide it during finishing.
• Having finished gluing one strip, we move on to another, performing the previous operations.

We perform grouting and apply a leveling layer

Following the application of plaster over the foam plastic on the mesh, we allow the plaster to dry before leveling the wall. You will need to use a special plastic float with a sandpaper cloth placed on it to perform grouting in order to accomplish this.

• Rough leveling is carried out with a plate with large grains, ideal smoothness is achieved with small ones. We rub the surface without applying force, without pressing, with smooth circular movements counterclockwise. During the work, we change the sandpaper several times.
• After grouting, we proceed to the final alignment of the wall, using a universal mixture. But in this case, we make the solution more liquid, so it will be plastic, easily hide all the flaws.

The easy actions listed below will be taken in order to plaster the wall:

• Apply the plaster to the spatula and smoothly rub it over the wall.
• The layer of plaster application will vary depending on the evenness of the surface, the quality of the first layer, grouting. It will be approximately 1-3 mm.
• The leveling layer is typically applied in the form of heels. In this case, it is necessary to avoid the coincidence of sections and joints of the mesh. Leave the solution to dry, but do not allow it to dry out, since it will then be difficult to rub. The optimal time to start grouting after the leveling layer is one day.
• Next, we carry out grouting in the manner described above. We try to do the grouting efficiently, ultimately obtaining a perfectly smooth surface.

Plastering foam has the ability to turn a basic, lightweight material into a well-finished, long-lasting surface that can be used for a variety of purposes. Although the procedure is simple, it needs to be done with care to guarantee a flawless, long-lasting finish.

You can achieve an aesthetic result that improves the structure’s insulation and protection by properly prepping the foam surface, using the appropriate primer, and mixing the plaster. The end product will be more durable and of higher quality if you take the time to follow these steps.

Plastering foam provides an economical solution that blends user-friendliness with expert outcomes, regardless of the size of the project. Anyone can achieve a polished, long-lasting finish with the appropriate technique.

Whether foam is being used for insulation or decoration, plastering it is an essential step in guaranteeing a smooth and long-lasting finish. In order to achieve a strong bond and an even surface, this process entails choosing the appropriate materials, applying a base coat that is appropriate, and using the right techniques. These steps ultimately improve the foam’s appearance and longevity.

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