Do-it-yourself wall insulation with foam



Comfortable atmosphere at home at any time of the year -it is a guarantee of good health and good mood. Many are trying to create the perfect indoor microclimate with the help of air conditioners and electric heaters, however, firstly, the systematic use of these devices is harmful to health, and secondly, in view of the constantly rising electricity prices, this is completely unprofitable from an economic point of view. Really increase energy efficiencyliving quarters can only be one way - to provide him with reliable thermal insulation. One of the most common methods today is wall insulation from the outside with polystyrene foam, and the popularity of this technology is explained quite simply: affordable material price, quick and easy installation, effective thermal insulation, resistance to moisture and aesthetic appearance of the finished object.

But so that the end result matches yoursexpectations, it is necessary not only to choose the right polystyrene foam, but also to know the technology of the work. All these subtleties will be discussed in this article.

Material selection

Foam plates differ not onlythickness, but also density, and this indicator should be taken into account when buying material. Wall insulation from the outside with low density foam is recommended only if in the future it is planned to equip the house with hard finishing materials (for example, siding), which will protect the insulation from mechanical damage.


If the foam boards have a high density, then the external plaster can also function as a protective layer.

“Right” and “wrong” warming

It’s not uncommon for homeowners to decidedo the internal insulation of the walls with foam with your own hands, mistakenly believing that this method is no different from the external thermal insulation of an apartment or house, but the difference in the effectiveness of these two methods is huge. In the cold season, the outer wall, insulated with polystyrene foam, warms up well and keeps heat from internal heating, providing a comfortable temperature in the room.

If the walls are glued with polystyrene from the insideon the other hand, they will not be able to “receive” heat from heating devices, although they will not be cold, but the “dew point” will shift deeper into the outer wall. As a result of this, moisture condensation occurs inside the wall, and at freezing temperatures it freezes. Thus, internal insulation entails a violation of heat transfer and the gradual destruction of the walls. That is why wall insulation from the outside with polystyrene is a more correct method.

Step-by-step technology of external insulation of the house

The insulation of the walls of an apartment in a multi-storey building isthe prerogative of professionals, but the owners of suburban real estate may well make their own walls with polystyrene foam. To do this, you just need to purchase the necessary number of relevant building materials, have the right set of tools on hand and try to comply with a certain technology.

Wall surface preparation

The quality and life of the insulation will bedepend, first of all, on the preliminary preparation of the insulated surface. If the house is new, the preparatory process is greatly simplified, but with the old buildings will have to tinker. The following are all required activities:

  • Dismantling of all elements located outside the house that may impede work (drainpipes, ventilation grilles, air conditioners, spotlights, facade decor, etc.);

  • Checking the quality of the walls. In the presence of plaster, they are tested for strength by tapping the surface. Exfoliated areas must be removed;
  • If there are concrete flows or surplusmortar between bricks, they are eliminated with a chisel. Cracks on the walls must be pre-primed, and after drying, sealed with cement putty;

  • Must remove moldfungus, rust, grease, salt deposits. If oil paint was used to paint the facade, it must be removed, because paint and varnish surfaces have low adhesive properties;
  • Walls with bumps and differences greater than 1.5 cm must be leveled. To do this, they are first primed, then “beacons” are attached, on which the plaster composition is applied;
  • The final step in preparing the walls is to coat them with a primer. The primer is applied in a single layer on the brick, and the cellular concrete walls are impregnated twice.
  • Installation of the start profile

    Wall insulation from the outside with foamfrom their lower border (it can be calculated by studying the project of the house). Using the hydraulic level, it is necessary to measure and mark this boundary around the entire perimeter of the house. A cord is pulled along the marked points, in parallel with which a starting profile is then installed. This profile will play the role of a “stand” for the first row of foam slabs so that they do not slide down while the adhesive mortar hardens.


    The width of the starting bar is selected inaccording to the thickness of the foam. The bar is mounted by means of plastic dowel nails (6 mm) and driven screws with washers. Fasteners are located at a distance of 30-35 cm from each other. The angular joints of the starting strips are made with an oblique cut or with the help of corner connectors. In order to avoid deformation of the structure due to temperature fluctuations, the ends of the profiles are joined by special plastic connecting elements. The lap joint is not allowed!

    Adhesive solution preparation

    Styrofoam sticks are availablespecial adhesive mixtures. The mixture is prepared according to the instructions, but even with a large amount of work ahead, do not immediately knead the whole bag, because the glue may thicken or dry if it is not used within one and a half to two hours.


    Pouring the recommended portion of water into a largea plastic bucket, glue is carefully poured into it, which is then mixed at low speeds with a construction mixer. It is a special nozzle inserted into a drill.

    “Beating” the solution lasts until all lumps disappear. After this mixture is allowed to stand for 5-7 minutes, and then continue the mixing process for a couple of minutes. All glue is ready to use.

    Installation of foam plates

    Glue can be applied to foam boards in different ways, depending on the evenness of the walls.

    If the surface drops are 1-1.5 cm,then the adhesive mixture is applied around the perimeter of the plate, with a 2 cm deviation from the edges. The thickness of the adhesive layer should also be 2 cm. 5-7 adhesive “beacons” of the same height are evenly placed in the center of the plate so that the foam sticks well over the entire area. To avoid air traffic jams, the adhesive strip cannot be made continuous - it should be dotted.

    If the walls are almost even with errors up to 5 mm, a special notched trowel with a comb tooth size of 1x1 cm is used, with which glue is applied to the entire area of ​​the plate.


    It is best to insulate the walls from the outside with foamproduce together - one smears, the second sticks. As mentioned above, the installation of insulation begins from the bottom, from the profile. The glued sheet is well pressed against the wall over the entire plane with the help of a half. To check the correct installation of each plate, use a level.

    Excess glue protruding from under the slabs is necessaryclean immediately to avoid the formation of large gaps between the plates. The maximum distance between the sheets should not exceed 3 mm. If large gaps could not be avoided, they must be repaired with building foam or long narrow strips of foam.


    The gluing of the second and subsequent rows of foam is offset with respect to the joints of the previous row by at least 20 cm, and ideally by half.

    Additional foam fixing

    To the next stage, namely, to consolidatemechanical insulation using special dowels for polystyrene foam ("umbrellas"), it is possible to proceed only after the adhesive has completely dried (2-3 days). The length of the dowels is selected taking into account the thickness of the plates and the adhesive layer, plus the depth of entry of the dowel legs into the wall (4-5 cm).


    In places (usually in the corners of plates and in their center),where it is planned to install “umbrellas”, holes are made through the foam, corresponding to the depth and diameter. Then, dowels are inserted into these holes until the caps come into full contact with the plane of the plate. The final fixation is carried out by driving dowels into the “body” of the foam by 1.5-2 mm.

    Insulation reinforcement

    Before reinforcing, all joints must be wiped with a special polystyrene grater.

    Then the entire surface should be coated with a primer. After it has completely dried, the foam walls are reinforced with a special reinforcing mesh and plaster mixture. This procedure is necessary in order to avoid cracking on the plaster at the joints of the foam boards, as well as for more reliable adhesion of the mixture to the surface of the insulation.


    It is most convenient to start reinforcing from the corners of the house and the slope lines. The finished solution is applied to a wall area of ​​approximately 1 square. m thin (2 mm) uniform layer.

    Next, a grid is laid on it, whichit is necessary to "drown" in solution with a spatula. If the mesh structure appears through the solution layer, an additional layer should be applied on top. Cloths of reinforcement are lapped together.


    After the reinforcing layer has dried,surface grout and subsequent primer. If foam walls are not planned to be covered with corrugated board or siding, then finishing putty is performed, after which the walls will be ready for final finishing operations (painting, decorative plaster, etc.)