Warming of the blind area and basement with various heat-insulating materials

Warming of the blind area and basement is another important detail in the thermal insulation of the foundation of the house. This set of measures will significantly reduce the cost of paying utility bills for heating, as well as eliminate the possible vertical movement of the blind area due to freezing of the soil. Of course, you can argue that just warming the walls of the house is enough, but even if you use the most effective heat-insulating material for these purposes, cold bridges will still form at the floor level. The reason for their occurrence is that the thermal conductivity of structural materials (brick, wood, concrete) is much higher than that of the insulation, and the basement of the house or the subfloor also turn out to be insulated, which contributes to the outflow of heat through the floor. Therefore, the foundation must be insulated.


  • Warming of the blind areas – from beginning to end
  • Polyurethane foam insulation
  • Expanded polystyrene or polystyrene as a heater
  • Basement insulation – getting ready for winter
    • We warm the base with polystyrene foam
    • Alternative insulation options
    • Warming of the blind areas – from beginning to end

      In general, the blind area is a concrete strip located along the entire perimeter of the building and protecting its foundation from the damaging effects of moisture. But this element of any country house is not as simple as it seems at first glance.

      Warming of the blind areas of the foundation, scheme

      The scheme of the insulation device for the foundation, blind area and basement

      The main complexity of the construction of the blind area is not in the process itself, but in the calculations, which depend on several factors – the type of soil and the width of the eaves. So, for example, on ordinary soils, the width of the blind area should be 20-25 cm greater than the eaves of the roof, and if the building is built on subsiding soils, then the width of the blind area should be at least 90 cm.

      You can insulate the blind area with different materials, but today the most popular are polyurethane foam and polystyrene foam.

      Polyurethane foam insulation

      Polyurethane foam – a sprayed thermal insulation material, which is characterized by extreme durability, low coefficient of thermal conductivity and high biological and chemical resistance.

      Polyurethane foam is applied directly to the rubble, which was previously poured around the entire perimeter of the building.

      Important: Do not apply polyurethane foam to the sand cushion, as the pressure created in the spray gun is so strong that it can blow sand away.

      The thickness of the layer of polyurethane foam, in principle, can be any, however, to insulate the blind area it will be enough 5-7 cm, because even the smallest layer of 5 cm successfully copes with the task assigned to it – eliminating freezing of the soil. This nuisance (if it suddenly happened) can lead to the formation of cracks on the foundation, the oscillation of the blind area and the penetration of moisture into the building. Thanks to polyurethane foam, such moments can be avoided, and besides, due to the fact that it is applied absolutely seamlessly and waterproof, you don’t have to worry about waterproofing.

      Expanded polystyrene or polystyrene as a heater

      This method of thermal insulation is relatively simple and cheap. Foam sheets are laid either on crushed stone or on roofing material (depending on what you use). For greater strength and reliability, they can be coated with adhesive, and it is recommended that the joints be foamed with mounting foam – so the water will not get inside. Sand or soil is poured over polystyrene foam slabs and rammed. And then it all depends on your preferences – either you fill it with concrete, or roll the asphalt, or decorate with stones and cobbles, or leave it as it is.

      Warming of the blind area and basement

      Warming of the blind area and basement with expanded polystyrene

      Basement insulation – getting ready for winter

      But the insulation of the base will require a little more time and will take a lot of effort. In general, a basement is the upper part of the foundation, which rises about half a meter above the surface of the earth. The basement is in conditions of high humidity, therefore it is best to use dense materials for its construction: burnt brick, concrete blocks, etc., and for its lining – plaster, ceramic tile or slabs made of natural or artificial stone. The basement must also be insulated wisely. Most often, extruded polystyrene foam is used for these purposes, which even in a humid environment has high thermal insulation characteristics..

      We warm the base with polystyrene foam

      To insulate the base, it will be enough to buy polystyrene sheets 10 cm thick. So, we proceed.

      First, we dig a trench with a depth of about 0.3-0.4 meters around the entire perimeter of the house. Then you need to cast the screed from expanded clay concrete, which we do ourselves, based on the following formula: 1 part cement, 6 parts expanded clay, 3 parts sand, 0.8 parts water and a tablespoon of shower gel or any liquid soap.

      Filling the screed to the bottom of the trench, and letting it dry, we begin to install insulation sheets, which for greater strength are lubricated with adhesive and fastened to the base. No matter how we try, the gaps will still be, but they can be eliminated with mounting foam.

      Important: do not forget that when installing polystyrene foam slabs, you need to take into account all technological holes (sewer, ventilation pipes, etc.) and make cutouts in appropriate places, or install embedded pipes and other elements through which utility networks will be drawn.

      Another very important point that cannot be missed: if the house does not have a basement, but there is a small subfloor that you do not use in any way, then you must leave openings (vents) for its ventilation. With the onset of cold weather, these holes are closed with plugs, and in the spring they are opened. Just don’t forget about it, because if the street has already had a high temperature for a long time, and the winter is still in the underground, then a lot of condensate will surely accumulate there, which, as you know, will not lead to anything good.

      Having fixed the sheets of expanded polystyrene, we lubricate its surface with glue so that expanded clay concrete better sticks. Next, we construct the formwork and fill everything with the prepared solution. As a result, we get a fully insulated and reliably protected from moisture and rodents base, which will serve you for more than a dozen years. And so that you enjoy not only the heat, but also the appearance of the basement of the house, you can finish it with decorative plaster, cladding or clinker bricks, tiles or natural stone.

      Basement insulation

      Fixing polystyrene foam on the base

      Basement insulation scheme

      Sectional warmed cap

      For basement finishes Reinforcing mesh and the material itself will be required. We fix the dowels on the insulation with a dowel and then on the adhesive composition or sand-concrete mixture we plant the facing material. For better adhesion with polystyrene foam on the sheets of insulation, you can make small notches.

      Important: make sure that the dowels enter the wall, otherwise all the work on decorating the basement will go down the drain – all your beauty will simply fall off with the heater.

      Alternative insulation options

      In addition to polystyrene foam, the base can also be insulated with polystyrene foam, and it can be both in sheets and in crushed form, and polyurethane foam. But in the old days, for the thermal insulation of the lower part of the house, a blockage was built, which, by the way, can be found today if you delve further into the province. The blockage was a formwork or wattle, which was installed at a distance of 40-50 cm from the walls of the house. The space between the wall and the wattle fence was covered with straw or a mixture of clay and straw with the addition of sand. Of course, it was impossible to get an energy-efficient house using this method, but it didn’t draw on the floor.

      To summarize, the insulation of the basement and blind areas is a necessity rather than a whim of the owner of the house. Someone will argue that these events are an unreasonable waste of time, effort and money, however, the fact remains – everyone who insulated the foundation, and with it the base and blind area, noticed a positive result in the first winter.