Insulation of the foundation in an energy-efficient house

The foundation is one of the most difficult elements — it is extremely important for the durability and strength of the building. The weight of the walls, ceiling and roof falls on it. At the same time, the foundation is designed to separate the entire house from the ground - to prevent the rise of groundwater and limit heat loss.


All the tasks that are set before the foundation are difficult to coordinate with each other. The method of foundation manufacturing commonly used in our country, although it is good in terms of strength, but it contributes to energy efficiency. Therefore, alternative solutions are being sought in energy-efficient homes. Hence the popularity of the foundation on the slab or the thermal insulation of walls and foundations entirely.


Of course, the higher the energy efficiency bar is set, the more significant the heat loss to the ground is taken into account. The foundation of reinforced concrete and plain concrete obviously requires thermal insulation, and it must be made of a moisture-resistant material. Extruded polystyrene (XPS) is very well suited for this role because it is less absorbent and more mechanically stable than regular polystyrene (EPS styrofoam).


In the case of a typical foundation, minimal insulation is applied externally on the foundation wall. Insulation of the entire foundation wall is especially important in houses with a basement. In this way, we create a thermal barrier between the basement and the ground. Regardless of whether the house has a basement or not, the insulation of the foundation wall should be combined with the thermal insulation of the walls above the ground.

Why is insulation necessary primarily from the outside of the foundation wall?


That's because the ground temperature changes the most there. Without thermal insulation, heat losses - especially in the area of the basement, that is, above the ground - will be very high. After all, the base is in contact with the outside air, the temperature of which drops to -20 °C in winter.


An excellent idea is to use extruded polystyrene foam for the formwork of the foundation. After pouring, it must be left, which will significantly insulate your foundation, but this also leads to increased costs.


An alternative option is to make a foundation slab. In this case, the insulation is placed under the load-bearing reinforced concrete slab so that it protrudes beyond its edges. As a result, the insulation of the slab can be combined with the insulation of the wall, ensuring continuity of thermal insulation. Most often, this method turns out to be simpler and ultimately cheaper than the insulation of a traditional foundation described above. e cig