Do-it-yourself wall insulation with expanded polystyrene

Recommendation points

• Preparatory stage
• Wet facade
• Thermal insulation

There are different ways to insulate walls with expanded polystyrene. Some are used only at the construction stage, for example, permanent formwork or well masonry, and there are those that are possible for an old house. And at least two such “universal” methods are feasible with your own hands.

Preparatory stage

The differences in the insulation of the new wall in comparison with the old one consist only in a more extended preparatory stage. Therefore, below is an instruction with a maximum list of preparatory work:

1. Dismantle all attachments, including ebbs and canopies. Ebb tides will have to be changed to wider ones, and the brackets for attaching elements of lighting, air conditioning and ventilation systems will have to be changed for longer ones (taking into account the thickness of the insulation).
2. They clean the wall from everything that impairs the adhesion of the adhesive mortar and expanded polystyrene plates – crumbling areas, old paint, efflorescence, dirt, etc..
3. Carry out cleaning and processing of areas affected by mold and moss.
4. Level the surface as much as possible – close up cracks and chips, knock down the build-up of mortars.
5. Apply a strengthening primer.
6. Mount new mounts to the wall for lamps, gutters, air conditioners, etc..

Wet facade

This is one of the most popular ways. Relatively low costs and uncomplicated technology are the reasons for this popularity..

In section, the insulated wall looks like this:

Wet facade device diagram: 1 – load-bearing wall; 2 – adhesive composition; 3 – expanded polystyrene; 4 – dowel; 5 – base layer of plaster; 6 – fiberglass mesh; 7 – finishing layer of plaster; 8 – decorative plaster; 9 – perforated corner

Already on the basis of this scheme, the basic principles of the insulation method are clear:

• beat off the lower level for attaching the basement strip;
• fix the bar, leaving a gap between adjacent sections to compensate for thermal expansion;

• the gap is calculated based on the fact that an additional 10 ° C (relative to the air temperature during installation) will give an increase in the length of each basement strip of 0.5 mm by 1 m and a decrease in the gap by 1 mm, as an example: at L = 2.5 m t₁ = 20 ° C and t₂ = 40 ° C the gap must be at least 2.5 mm;
• apply an adhesive solution to the surface of the foam board and distribute it with a notched trowel;

• installation starts from the corner of the house;
• insert the first sheet into the basement strip and press it against the wall;
• insert the second sheet, press, align both sheets relative to the vertical level and each other;

• the entire first row is fixed, the second starts with the displacement of the plate relative to the first (the amount of displacement is at least 20 cm);
• window and door openings are insulated in such a way that the corner of the opening is cut into the foam plate, and does not fall on the joint of adjacent plates;

• mechanical fastening with umbrella dowels is carried out after the glue has dried (5 pcs per 1 m² – one in the center, the rest at a distance of 5 cm from the edge of the corners);

• a base layer of glue is applied (about 3 mm) and a reinforcing mesh is pressed into it (with an overlap of adjacent canvases);

• reinforce all outer corners with a perforated corner;
• corners in the plane of the openings are fixed with additional mesh strips;
• apply, level and rub another layer of adhesive solution;
• after the solution has dried, the surface is sanded, primed, plastered and painted.

Thermal insulation

The main disadvantage of do-it-yourself insulation using the “wet facade” technology is plastering work. And although the facade plaster is bought in the form of a ready-made dry mixture, to which it remains only to add water, the process of applying and grouting the layer itself requires a certain skill. In addition, not everyone likes painted plaster facades – they quickly get dirty near roads and in industrial areas..

Thermal panels are devoid of these disadvantages. This name unites the whole direction of facing facade panels with insulation, but all of them can be grouped into two large classes:

• three-layer (OSB board – polyurethane foam – decorative layer);
• two-layer (expanded polystyrene – decorative layer).

Naturally, the second option is cheaper and more popular..

For reference. Expanded polystyrene ranks second among all types of thermal insulation materials (according to various sources, from 20 to 30% of the market).

The following options can be found as a decorative layer:

• clinker tiles;

• polymer sand tiles (facing brick);

• chipped stone tiles;

• plaster “stone chips”.

Only facade thermal panels with stone chips are attached to the wall with an adhesive mortar, other types can only use mechanical fasteners.

But each manufacturer has its own mounting scheme. The general sequence of fastening is as follows:

• prepare the surface;
• beat off the lower horizontal level;
• fasten the starting profile in the form of a corner or a bar (for low-rise buildings, this stage is optional);
• installation begins with a corner element;

• the next panel is “pushed” by the protruding tile into the grooves of the corner element;

• each panel is fixed according to the manufacturer’s technological map (usually there are markings on the panel for the attachment points);
• if the wall is uneven, then leveling is carried out using vertical beacons with foam blowing of the seams and joints between the panels;
• the second row starts from the corner with a half-size panel, if there is no such size in the manufacturer’s assortment, then the panel is cut off from the other side from the corner, and the next cut panel is attached to it end-to-end;
• the design of openings is also made either from special additional panels (vertical and horizontal), or by trimming ordinary panels;

• internal corners are made by trimming ordinary thermal panels.

The entire volume of work on decorative wall decoration with your own hands is reduced only to grouting.