How a house is insulated with polystyrene outside - different options, rules for preparation and installation

When the building is completed, many property owners think about the question of how to insulate the house with polystyrene from the outside.

Thanks to proper insulation, money is saved on the heat carriers consumed in winter, in addition, it is much cooler in an insulated building in the summer.

According to the calculations of specialists, even the most massive, thickest and strongest walls are almost impossible to completely protect from freezing in winter, if the building is not insulated.


  • What material is better to use for wall insulation
  • Calculation of the thickness of the insulation
  • Technology of insulation of a brick house with polystyrene outside
  • Mounting on fasteners, adhesive, combination version
  • Preparing the walls
  • Panel mounting
  • Frequently made mistakes when insulating a house with your own hands
  • Insulation of the facade with Penoplex, what are the advantages
  • Features of internal insulation

What material is better to use for wall insulation

Today, many different heat-insulating materials are made that are used for insulation.

Here is a list of the most popular and commonly used thermal insulation products:

  • polystyrene;
  • mineral wool;
  • Styrofoam;
  • penoizol;
  • polyurethane.

These materials are best suited for insulation and are used more often than other products. But which of these insulation products is the best?

It all depends on the individual characteristics of the building. Only experienced, professional specialists will be able to select the most suitable material after carrying out all calculations and assessing the situation.

Calculation of the thickness of the insulation

To avoid heat loss as much as possible, it is important to correctly calculate the thickness of the insulation boards. But if you choose an overly thick material, then this will lead to unnecessary material costs, while energy efficiency will not increase. Thanks to the correct calculation of the thermal insulation layer, it will be warm inside the house in winter and cool in summer.

On the Internet resources of many manufacturers of insulation materials there are special online calculators, they make it possible to very easily and quickly read what thickness the thermal insulation should have, and what type of insulation is suitable for a particular situation.

Each of the insulating materials has its own thermal conductivity coefficient. Depending on this coefficient, the formula calculates the required thickness of the insulation boards, it is influenced by the thickness of the walls, climatic factors and other nuances.

The material from which the house is built plays an important role in calculating the thickness of the insulator. Walls made of concrete, brick, hollow blocks and other building materials have different thermal conductivity indicators, depending on this, the thickness of thermal insulation is selected.

So, if the thickness of the brick wall is 25 centimeters, then the thermal insulation layer is chosen, at least 4 centimeters thick. And if the thickness of the wall is 50 centimeters, then it will be enough to insulate it with expanded polystyrene, the thickness of which is 3-5 centimeters, depending on climatic features.

Technology of insulation of a brick house with polystyrene outside

After the optimal insulation material has been selected, it is important to choose the right technology for fixing the plates to the walls.

There are three main methods for attaching panels to the outside of a brick house:

  • With plastic dowels. Each polystyrene sheet is fixed in at least 5 places with special plastic dowels with a wide cap, while at the edges these caps overlap the joints of 2 sheets. This is the most difficult and time consuming method, however, it is considered the most reliable.
  • With special glue. This technology is used when the walls of the building are leveled with plaster or putty as much as possible, and are perfectly flat. The adhesive is applied to the surface of the polystyrene plates, after which the sheets are pressed against the wall with force.
  • Combined option. In this case, both special glue and dowels with large-diameter caps are used. First, the sheets are glued to the wall surface with an adhesive, after which they are securely fixed with several plastic dowels.

Which of the above methods to use for each individual case should be decided by experienced specialists.

They will analyze all the parameters and nuances, taking into account the features of the walls and the load that the insulation will provide along with the finishing, after which they will select the most optimal option.

Mounting on fasteners, adhesive, combination version

For mounting sheets of insulation on fasteners, plastic dowels with wide caps are purchased. These elements are popularly called umbrellas or fungi. Under each of them, holes are drilled in the wall with a puncher, umbrellas are inserted and plastic nails are hammered in with a hammer.

To install thermal insulation on an adhesive, it is important to choose the right adhesive that is suitable specifically for outdoor work. The composition must be frost-resistant and must be suitable for gluing polystyrene. In the store, be sure to read the instructions for the use of adhesive products.

The combined option is the most common, as it is the most reliable.

First of all, the polystyrene sheets are fixed on the glue solution, and then fixed with plastic dowels. In this case, it is important to choose the right glue and the length of the dowels, which should be several centimeters larger than the thickness of the polystyrene.

Preparing the walls

When all supplies and tools are prepared, they begin to prepare the walls.

Proper preparation includes the following work:

  • old paints and varnishes and finishes are removed;
  • remove all flaky and crumbling areas;
  • remove all facade elements that will interfere with the thermal insulation of the house;
  • using putty or cement mortar, they cover up cracks, potholes, depressions, seams and other damage, the depth and width of which is more than 5 millimeters;
  • moss, mold, fungus, if any, are removed from the surface of the walls;
  • one or two coats of deep penetration primer are applied. It is imperative to prime those areas that are constantly exposed to water and moisture, this includes the foundation and basement.

When all of the above preparatory work is completed and the primer is dry, they begin to fix the polystyrene sheets.

Panel mounting

Most specialists involved in house insulation recommend using a combined installation option for polystyrene panels.

This method is as follows:

  • The starting profile is mounted at the bottom of the building along the entire perimeter of the house. It is important to install this profile strictly horizontally using a level, all polystyrene sheets will be installed on this profile. The profile is fixed with dowels.
  • Prepare the adhesive according to the instructions on the package.
  • Glue is applied over the entire surface of the panels, the thickness of the composition should be from 0.5 to 1 cm. It is important not to save glue so that the sheets of insulation are securely fixed to the wall.
  • The first slab is installed from the corner of the house, it is placed on the profile. It is important to press the sheet against the wall so that it is securely fixed.
  • Each subsequent sheet is fixed on an adhesive composition, with an indent of 0.5 cm from the previous panel.
  • It is important to arrange each top panel in a staggered manner, it is necessary to ensure that the seams of the plates are out of order and do not coincide, leaving gaps of 0.5 cm between each subsequent row.
  • After gluing each sheet with a perforator or drill, holes are drilled through it in the wall at the corners of the slab and in the center. Plastic dowels are inserted into these holes and plastic nails, which come with the dowels, are driven in. It is important to sink each dowel by about 1-2 mm in polystyrene, so that later plastic elements do not interfere with the finishing.

When all the panels are fixed, the seams between them are filled with a sealing compound.

This is the most reliable method of fixing insulation, which allows you to reliably fix polystyrene to any type of wall.

We offer you to watch an interesting video about that. how to insulate a house outside with polystyrene:

Frequently made mistakes when insulating a house with your own hands

Here is a list of the main mistakes that non-specialists make when insulating houses:

  • save on density and thickness of polystyrene;
  • using an unsuitable adhesive composition;
  • choosing a cheap mesh and installing it incorrectly;
  • perform work at too low or, on the contrary, too high air temperature;
  • carry out insulation inside the house, and not outside;
  • do not cover the insulation on top with a reinforcing layer;
  • use extruded polystyrene foam, which is not suitable for facade insulation.
  • Avoiding these mistakes, you will definitely be able to properly insulate the building with your own hands.

Let's watch a video with an analysis of the most common mistakes made during insulation:

Insulation of the facade with Penoplex, what are the advantages

Penoplex is well suited for thermal insulation of walls, this material has the following advantages:

  • long service life;
  • small weight;
  • practical waste-free;
  • not flammable;
  • low rate of moisture absorption;
  • low water vapor permeability;
  • fungi and mold do not start.

In addition, penoplex has a minimum heat conductivity, so it is often used during insulation.

Features of internal insulation

Experienced experts do not recommend insulating houses with foam or polystyrene from the inside, as condensation forms under the slabs, as a result of which mold and fungi develop. Internal insulation reduces the area of ​​the room and shifts the dew point, as a result of which the thermal insulation properties of the walls decrease.

If the owner nevertheless decides to mount the thermal insulation sheets inside the room, then it is necessary to act according to a technology identical to external insulation.

So, following the recommendations and tips from this article, you can successfully insulate the house from the outside using polystyrene sheets. But if you do not have the necessary skills and experience in this area, it is better to entrust the work to qualified specialists.

Watch the video: Is polystyrene external wall insulation cost effective? (July 2021).