Insulation of the basement with expanded polystyrene

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Insulation of the basement with expanded polystyrene
Insulation of the basement with expanded polystyrene

Specificity of the building basement thermal insulation with expanded polystyrene, advantages and disadvantages, preparation for insulation, main work, finishing of the thermally insulated surface. Warming the basement with expanded polystyrene is an excellent method of thermal insulation that allows you to reduce freezing of the building foundation and, accordingly, reduce the cost of paying utility bills. Future comfort and an increase in the service life of the building depend on how well the work is done.

Features of the use of expanded polystyrene when insulating the basement

The use of expanded polystyrene when insulating the basement

Expanded polystyrene is the same foam produced using new technologies, it is more durable and is most often produced in the form of plates. Foamed polystyrene foam is an excellent choice when it comes to arranging or insulating basements, basements, insulation of foundations that are exposed to groundwater.

It owes its heat engineering characteristics to a special structure and composition, in which up to 98% is taken away by the air mass. Moisture does not penetrate into its cells, and, in addition, the material has practically no temperature restrictions for use in residential and industrial buildings for various purposes. Thanks to this, PPS (expanded polystyrene) is able to withstand 80 or more cycles with complete freezing and subsequent thawing. The research carried out allows us to calculate the operational time during which the material will not lose its key qualities. On their basis, manufacturers began to give a guarantee of up to 60 years of the impeccable performance of this heat insulator of the functions assigned to it.

It is necessary to insulate the base with polystyrene foam for several reasons:

  • As a result of such works, heat loss will be reduced by 10-15%.
  • Expanded polystyrene protects the support structure from groundwater.
  • It prevents condensation from forming on the walls of the base / plinth, protecting the building materials.

Warming the basement of the house with expanded polystyrene, both external and internal, gives the same result. Differences are visible only during finishing. When insulating the outside, additional finishing is needed. It is better to do heat insulation work at the time of laying the foundation, but if this is not done at the time of construction, then it is possible in an already built building, it is necessary to select only the right insulation and follow the recommendations for their use. Warming the basement makes sense even when the basement is not in use, this will protect the foundation from unforeseen weather influences.

The question may arise about the advisability of protecting the basement in a situation where the walls have already been insulated. But, no matter how good insulation is used on them, if the floor and basement are not insulated in the house, then cold air flows will penetrate into the room, since the thermal conductivity of the main structural materials (brick, concrete, wood) is higher than that of the insulating material.

Advantages and disadvantages of thermal insulation of the basement with expanded polystyrene

Expanded polystyrene for base / plinth insulation

Insulation of the basement with extruded polystyrene foam makes it possible to maintain its thermal insulation properties even in extremely humid environments. Compared to many other materials, this insulation is able to withstand impressive loads, preventing subsidence. Expanded polystyrene has other advantages in application:

  1. Frost resistance;
  2. High thermal insulation characteristics;
  3. Not affected by moisture;
  4. Well mounted, easy to cut;
  5. The material is relatively inexpensive;
  6. The service life is 40-50 years.

Among the shortcomings, it will be fair to highlight the following:

  • The material is subject to combustion, therefore, the basement of the building must be treated with non-combustible materials before laying.
  • It absorbs moisture well, therefore, before installation, it is necessary to treat the base with waterproofing materials.
  • The heat insulator can be damaged by rodents, and therefore it is necessary to install a reinforcing mesh.
  • It is exposed to mechanical damage - filling it with soil, you will need to install protection in the form of shields or reinforcing mesh.
  • Not recommended for use in buildings subject to ground movement.

Technology of basement insulation with expanded polystyrene

Do-it-yourself insulation of the basement with expanded polystyrene can be done both in a house under construction and in an already commissioned one. It is carried out both inside and outside the building, but the outside is the most effective, since the bottom of the building together with the walls will form a single heat-insulating layer.

Preparatory work

Cleaning the base before insulation

The base, which will be insulated, is freed from dirt, all kinds of debris, grease stains, and cleaned of soil. If there is roll-up waterproofing, it must also be removed.

When buying expanded polystyrene, you need to know the thickness and its density. As a heater, it is worth taking material with flame retardant additives or treating it with non-combustible materials.

The main tools for performing insulation work are as follows: a hand saw or a hacksaw (you can use it to cut an insulator), a spatula, a comb, a working bucket, a wooden hammer, a level, a plumb line, a drill, a trowel, a sharp knife-cutter, clean rags.

Materials used for fastening extruded polystyrene foam: the material itself, a reinforcing mesh 2, 3 times higher than insulation, glue, polyurethane foam, umbrella plugs, primer, decorative plaster, brick.

Installation instructions for extruded polystyrene foam

Installation of extruded polystyrene foam

To calculate the required amount of material, you need to know its dimensions. We measure the base from all sides. If the developer does not want to insulate the terrace, then we subtract the length of the terrace from the total length of the basement. Let's give an example. The walls of the house, according to calculations, have a length of 110.8 m.Each side of the terrace has a length of 5.6 m, in total 22.4 m. From the calculation, we also subtract the length of the porch - 3.2 m. porch, we get the required length of 85, 2 m. Determine the height of the insulated surface - it is equal to 0.8 m. We multiply these two indicators and get the size of the area that needs to be insulated - 68, 16 m2… Insulation of the basement inside or outside is performed in the same way. The difference lies only in the location of the waterproofing and vapor barrier material. If the work is done from the outside, then first the vapor barrier material is attached, then the thermal insulation and on top of the waterproofer. If they are insulated inside the basement, then the waterproofing material is first glued, then the insulation, and the vapor barrier is fixed last.

The algorithm for carrying out thermal insulation based on expanded polystyrene is as follows:

  • It is necessary to cut sheets of insulation equal to the height of the base. Next, cut the reinforcing mesh into pieces of the required length and width, and its length should allow you to wrap a sheet of expanded polystyrene.
  • We attach a heat insulator to the cleaned surface of the basement after the hydro and vapor barrier material, based on where it is insulated: inside or outside.
  • The reinforcing mesh is fixed in advance or together with a polystyrene foam plate. The cut mesh pieces are overlapped with a 10 cm overlap.
  • We attach the boards with contact glue. It is applied with a spatula and a comb along the perimeter of the board and in the middle, kept for 1 minute, and firmly attached to the base.When fixing the plates, you need to make sure that there are no gaps; pieces of insulation can be used to eliminate them. You need to wait a few minutes, and you can start fixing the next plate.
  • It is necessary to fix it with a level, this will prevent distortions. Expanded polystyrene slabs have an L-shaped recess along the entire perimeter, which allows the slabs to be joined in the lock, blocking the path of cold air. If it is necessary to achieve a greater thickness of thermal insulation, then the insulation is laid in two layers, and the second is applied so that it covers the joints of the first.
  • The remaining seams after fastening are filled with polyurethane foam. Residues after drying are removed with a knife.
  • The lower layer of insulation must be reinforced into a solid base, a special ledge on the foundation. If it is absent, you can drown the heat insulator into the sand and gravel backfill, on which the foundation itself is installed. The last layer of the heat insulator is attached to the upper base of the plinth and is connected to the wall heat insulator. If this is not done, then cold air will penetrate into the room.
  • After a day or two, after the glue has dried, the plates are additionally attached to the base with the help of dowels - nails with a wide head. A hole is made through the slab 3 mm longer than the nail itself. The dowel is hammered and a nail into it. Each slab requires at least 4 fasteners, so as not to make an extra number of holes, you can fix them in the joints of the slabs. A recess is made in the slab a little longer than the dowel, after that it is hammered in, and then a nail is driven into the same place. Plastic dowels with a wide head hold the insulation plates perfectly and do not let air through.

After the completion of the thermal insulation work, they are finishing the basement. Since the insulation can be damaged, the bottom of the building is covered with decorative finishing boards or plastered. If you plan to cover the base with a layer of plaster, then a fiberglass mesh is fixed over the heat insulator. When the thickness of the plaster reaches more than 3 cm, a mechanical mesh is taken for reinforcement work, which is fixed with disc dowels. The facing material is fixed either to the plaster or directly to the wall, the dowels are driven into the wall through the heat-insulating material.

Surface finishing

Stone cladding of the plinth

When finishing the basement, the following options are used: the use of decorative plaster, facing with a brick (stone). The first option is used both indoors and outdoors. The second is for outdoor use only.

Before applying decorative plaster, you must first sketch out a primer, for this it is preferable to use products from the Contact-plus production series. After applying the primer, we will put a decorative plaster called "bark beetle". The consumer is offered both colored compositions and mixtures, which can subsequently be painted.

When using plaster of the "bark beetle" type, the technology of working with it must be observed. It is applied with a metal spatula. After that, the surface is cleaned with a float, making movements up and down or in a circle. The final drawing depends on the movements performed. After letting the surface dry a little, you should go over it with a float with great effort. The paint must be applied to the base after the plaster is completely dry, it is recommended to do this in 2 layers.

Facing the plinth with a brick makes it possible for the insulation to provide resistance to soil pressure and increase its thermal insulation properties, as well as give the insulated surface an aesthetic appearance. For cladding, it is not necessary to buy new brick, if unused from the masonry of the house remains, it can be used. After laying it is covered with decorative varnish.

The masonry is carried out as follows.They retreat 10-12 mm from the insulated basement, lay out the first layer of brick, lubricating it with a solution consisting of one part of cement, three parts of sand and water. After laying the 1st row, a bunch is made: directly above the first row, nails with a diameter of 0.5 cm are driven into the wall, the nail should go into the wall by at least 2 cm, and the head of the fastener should lie on the brick. Then the laying is continued, the dressing is done after every 3-4 rows.

How to insulate the base with expanded polystyrene - look at the video:

Insulation of the basement with expanded polystyrene is a completely affordable construction technology that is used both indoors and outdoors. Thermal insulation works are performed quickly enough, and with careful maintenance, the basement insulated with expanded polystyrene can be used for more than a dozen years.

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