Styrofoam plaster

Rybnikov Alexey

Expanded polystyrene is a building material that is used to protect the house from the cold. However, the insulation itself needs protection, since it does not differ in strength. To do this, use plaster. The composition extends the operating period of polystyrene foam and performs several more functions.

Styrofoam plaster

Why plaster polystyrene?

Plastering of polystyrene foam is carried out in order to protect the insulation. The material is “afraid” of water, sunlight and temperature changes. The negative impact of the environment over time destroy polystyrene foam. To prevent this, apply plaster. The tool provides waterproofing of the material, protection from ultraviolet radiation and frost. As a result, the shelf life of polystyrene is increased. Plaster also protects the material from mechanical damage.

Extruded polystyrene foam is also used to warm the house. Such a material is more durable than polystyrene foam. The insulation does not collapse due to frost or sunlight. However, this material also needs protection. In places of cut, the protection is not as strong as on an integral surface, therefore, in these areas the sun and temperature changes destroy the structure of the insulation. Therefore, the plastering of extruded polystyrene foam is also relevant.

Application of plaster on polystyrene foam

Types of plaster for polystyrene foam

How to plaster polystyrene foam - it is not surprising that amateurs have this question. For this material, mixtures with reliable adhesion to smooth and brittle materials are suitable.

Mineral

Such styrofoam plaster contains cement, mineral components and lime. The material has good adhesion with polystyrene foam, withstands temperature extremes and other negative environmental manifestations. The operating period of mineral plaster is 10 years. The tool provides waterproofing of the surface, but the material has vapor permeability. The product is environmentally friendly and does not require special care. The disadvantage is poor elasticity. This means that cracks occur on the surface over time.

Mineral plaster

Acrylic

Such facade polystyrene plaster contains acrylic resins, plasticizers, modifiers and mineral components. The product withstands temperature extremes, has moisture resistance and vapor permeability. The tool increases the strength of expanded polystyrene and has good adhesion. The operational period is 15-25 years. Disadvantages - high price. The approximate cost is 1,500 rubles per 25 kg. In addition, the plaster absorbs dust and is poorly cleaned, and also changes color under the influence of ultraviolet radiation.

Acrylic plaster

Mineral and acrylic plaster, in turn, are classified as follows:

• With adhesive. Such plaster is applied under a decorative coating.
• Decorative. The tool is used to complete the finish. This plaster is used for outdoor applications.
• Universal. Such a stucco-adhesive mixture for expanded polystyrene contains coarse and fine-grained additives, therefore it is used both for the reinforcing layer and for decorative coating.

Adhesive plaster

Calculation of material consumption

Plaster consumption is indicated on the packaging material. However, such information is not always accurate.Consumption increases or decreases depending on the consistency of the solution and other factors. Therefore, professionals are advised to calculate according to the instructions on the packaging, how much approximately the plaster on one wall will be required. After completion of the work, it will become clear whether the calculation is correct or more or less material is required. Then you can buy material for processing the remaining surfaces.

Tools and materials

To plaster polystyrene foam, you will need:

• set of spatulas for applying material;
• drill with mixer nozzle or industrial mixer to knead the solution;
• a clean bucket for plaster;
• grater for grinding the surface;
• fiberglass mesh;
• construction knife;
• plaster;
• water for mixing the solution.

Styrofoam plastering tools

Building foundation preparation

Styrofoam plastering, as the video tutorials show, begins with the preparation of the building foundation. The job is to align the hats of the screws. Fasteners should be below the surface of the polystyrene foam by 1 mm. Those screws that do not satisfy this requirement are screwed or twisted to the desired level. After that, fill the joints between the plates with foam. Check the surface for protruding areas. If you find large differences on a building base, clean the defects with a building grater. Then make notches on the surface. Using a needle roller (as in the photo below), draw diagonally across the surface. The distance between the strips of notches is 5 cm.

Needle roller

Application Technique

When the surface is ready for finishing, non-professional masters have a question - how to plaster polystyrene foam? The work is carried out in several stages. Here is the instruction for plastering insulation:

• Replace the solution. The rules for preparing the plaster are indicated on the packaging.
• Start with reinforcing corners and slopes. Cut a fiberglass mesh into pieces, 30 cm wide. Apply a solution to corners and slopes. After that, fix the grid. Press it into the composition and pass on top with a spatula.
• Fix fiberglass mesh to the walls. The technology is the same as reinforcing corners.
• Take a break to dry the composition. This takes 2 hours. After that, grind the material with a construction grater. Do not make the surface smooth, otherwise the next layer of plaster will be poorly applied.
• When the surface is polished, suspend work for a day. It takes so much time for the material to solidify completely.
• Prepare a solution. Apply the product on the wall and take a break to dry.
• Strip the surface with a construction grater. In this case, roughness is not left, since the surface should become smooth for subsequent finishing. On this work is completed.

A reinforcing mesh is installed before the plaster

Features of plastering extruded polystyrene foam

If we talk about how to plaster extruded polystyrene foam, then the same compositions will be suitable for this material as for expanded polystyrene. Therefore, acrylic and mineral formulations are used.

It is important to know how to plaster extruded polystyrene foam, as well as how to do it. Since such a heater differs from polystyrene foam, several factors are considered when working with it:

• the material does not absorb moisture, so if liquid is present on the surface, then it is absorbed into the plaster layer;
• plaster and extruded polystyrene foam have a different temperature coefficient of expansion, which often leads to peeling of the coating;
• the structure of the material is non-porous, therefore it is difficult to apply the solution to the surface.

To understand whether the stucco will adhere to the surface or not, do a test. To do this, apply the solution to the extruded polystyrene foam and leave it to harden for 24 hours.If the composition does not hold on to the base, then increase the adhesion of the insulation. To do this, reprocess the material with a needle roller and apply the primer. When the primer is dry, fix the fiberglass mesh to the surface. After this, apply the plaster. In order to keep the solution firmly on the surface, the layer thickness should not exceed 3 mm.

The video in this article disassembles the rules for plastering expanded polystyrene.

It is not as difficult to apply plaster on polystyrene with your own hands as it seems at first glance. If you study the technology of using the composition, then even an amateur without experience in construction will cope with the work.