How to insulate the foundation of a private house with your own hands: step by step instructions + Video

Thermal insulation of the foundation is the most important stage in building a house. It is as important as wall insulation. Moreover, in harsh climatic conditions, characterized by freezing of the soil to a great depth.

[contents ]

An uninsulated foundation causes serious heat loss, is dangerous for freezing and, consequently, destruction of underground structures.

Thermal insulation of the foundation from the outside significantly reduces heat loss, and serves as reliable protection of the base of the house from the influence of groundwater and negative temperatures.

Particularly dangerous for building foundation structures is freezing of heaving soils, on which houses with a pile-screw foundation are usually erected.

Why is it necessary to insulate the foundation

To avoid negative impact on the foundation of the external environment, they resort to such measures as waterproofing the foundation and its insulation.

The largest volume of cold air enters the building through the foundation. And if the house has a basement used for any functional purposes (garage, billiard room, laundry), then special attention should be paid to its thermal insulation.

An unheated basement does not need thermal insulation.

But it is necessary to insulate the basement of the foundation, especially in houses built on piles, in order to reduce heat loss at the floor level of the residential floor. Insulation of the basement helps to retain heat in the house, cutting off the path of cold air into the house.

In addition, the basement insulation layer plays a partial role in its waterproofing.

This means that the thermal insulation of the foundation:

• reduces heat loss;
• reduces heating costs;
• reduces the effect of soil heaving on the foundation;
• stabilizes the temperature inside the building;
• prevents the formation of condensation on the inner planes of the walls;
• performs mechanical protection of waterproofing and foundation structure.

What kind of insulation is more effective

There are two ways to insulate the foundation - insulation at the stage of pouring and subsequent insulation, produced after the concrete casting has solidified.

The first is the most preferable of them.

The most correct approach to warming the foundation during the construction process is fixed formwork. It is a structure inside which a concrete solution is poured. At the stage of its solidification, it plays the role of an ordinary formwork, but after it is not removed, it remains as a layer of insulation.

Usually fixed formwork is made of expanded polystyrene boards.

This type of insulation has a high cost, but in the future, such a foundation does not need additional insulation.

Insulation is most often carried out outside, because with outside insulation, as opposed to inside, both the premises of the house and the foundation itself are protected.Insulation of the foundation from the inside is most often resorted to if external insulation is impossible.

Materials and methods of warming the foundation

Insulation work begins with the selection of an insulating material that should not deform under soil pressure and absorb moisture.

Today, the choice of materials and methods for insulation is very diverse:

• backfilling with sand, expanded clay or earth.

• insulation with foam plastic plates and its analogues: foam, polystyrene.
• insulation with mineral wool;
• insulation with polyurethane foam.

All these materials are suitable for insulating private wooden, brick and block houses and differ in the values ​​of thermal insulation parameters and cost. For the best choice, you need to study their pros and cons.

Insulation of the foundation with sand and expanded clay

Until recently, this was the most popular way to insulate the foundation from the outside, associated with their ability to remove moisture and create an air gap near the walls of the foundation.

The advantages of the method include the low cost of the material and the ability to make thermal insulation by hand. At the same time, the backfill layer simultaneously performs the functions of waterproofing and reduces soil pressure during heaving, which allows it to be used on clay soils.

Execution technology:

1. The first step is to prepare a pit on the outside of the perimeter.
2. Drainage is done at the bottom of the pit: geotextiles are laid, covered with rubble, on which a perforated pipe is placed on top, and then again a layer of rubble. The pipes are tied and led into the well.

3. The foundation is cleaned and dried, and then it is waterproofed.
4. Fill the prepared trench with sand or expanded clay, tamping it in layers.

Warming with mastics

A certain insulation can be achieved during waterproofing works. For example, vertical foundation walls are recommended to be covered with several layers of bitumen mastic. This insulates cracks and small holes in the joints of the slabs through which heat escapes.

After that, a roll waterproofing material is applied to the side surfaces. It will be an additional layer of thermal insulation.

Thermal insulation of the foundation using mineral wool

This method is used extremely rarely, because for its implementation it is necessary to erect a frame, ensure good protection of the mats from getting wet, and also erect a protective wall from any finishing materials.

Technology of execution:

1. The surface of the foundation is cleaned and dried, defects are eliminated.
2. A frame for mineral mats from a metal profile is made on it.

3. Heat-insulating mats are placed on the frame and fixed. The surface of the insulation is closed from external moisture with a vapor-permeable wind-waterproof film.
4. Protective walls made of bricks or a ventilated frame are erected.

Insulation of the foundation with foam plastic

A modern and very effective way of high-quality thermal insulation of the foundation walls. Its advantage lies in the high thermal insulation characteristics of the material, ease of work, material resistance to mechanical damage and stress.

The disadvantages are the need to prepare the foundation surface, protect the foam from rodents, and also suitable waterproofing.

Execution technology:

1. The foundation is dug up, cleaned and dried. Remains of bitumen, fat, oil are removed from its surface.
2. Make foundation waterproofing.
3. The foam boards are laid with glue sold as a dry mix.

4. The surface of the foundation is protected with a reinforcing mesh from rodents, laying it on the same glue. Then the lower part of the foundation is backfilled with sand, and the upper part is fixed using the dowels intended for this.

Insulation with polyurethane foam

Polyurethane foam is a modern material for thermal insulation and sound insulation both outside and inside the premises. For its application, it is necessary to have special equipment that sprays polyurethane foam layer by layer on the required surface under high pressure. The thickness of the polyurethane foam layer should be 5 cm.

A similar insulating effect can be achieved using a layer of expanded polystyrene with a thickness of 12 cm.

The advantages of insulation with polyurethane foam are:

• longevity;
• high adhesive properties;
• no need for additional vapor and waterproofing.
• low vapor permeability;
• seamless coating;
• reliability; ne
• low heat permeability;

Among the disadvantages are the need use of special equipment and gradual destruction from solar exposure.

Thermal insulation with expanded polystyrene

Plates from extruded expanded polystyrene almost does not absorb and do not let water through. Therefore, this material retains its thermal insulation characteristics for a long time.

Advantages of insulation with this material:

• long service life;
• strength;
• constancy of thermal insulation properties;
• "inedible" for rodents.

When insulating with expanded polystyrene, it should be remembered that:

• the corners of the structure need "reinforced" thermal insulation,
• for warming the soil along the perimeter of the building, a layer of polystyrene foam should be placed under the blind area,
• the width of the blind area should correspond to the depth of soil freezing in the given climatic conditions.
• before insulating the foundation of the house, the surface of the walls must be leveled and waterproofed on it;
• the plates are fixed by applying glue to them or "melting" the bituminous waterproofing, to which it is then pressed and held for the time necessary plate for solidification.

How to insulate a shallow strip foundation

The installation of the slabs should be started from the bottom, the rows should be joined end to end. The thickness of the slabs must be the same.

Vertical seams of adjacent rows should be staggered.

Seams between boards with a thickness of more than 0.5 cm must be filled with polyurethane foam.

Select the adhesive based on the waterproofing material. When using roll and mastic materials based on bitumen, bitumen mastics that do not contain aggressive ingredients for expanded polystyrene are used as glue.

Before insulating the foundation from the outside, be sure to wait until the bituminous waterproofing is completely dry.

Glue is applied to the slabs located below the soil level in a point, which allows condensation between the insulation and the foundation wall to drain down.

Plates in the ground are attached only with glue and pressed down with a layer of earth.

For slabs that are above the ground, it is imperative to use fixing plugs.

How to insulate a monolithic foundation slab

For the most effective thermal insulation of the floor and basement, you need to take care of the insulation of the base plate.

For this, the insulation is placed on top of the waterproofing layer. Then, when used for pouring a power floor, knitted reinforcement is used, while it is enough to cover the heat insulator with a plastic wrap with an overlap of 10-15 cm and gluing with double-sided tape.

When using a welded reinforcing structure, on top of the film it will be necessary to make a protective screed made of concrete or cement-sand mortar, and already on top of this, perform welding work.

It should be noted that it is more correct to engage in laying and insulating the foundation in the warm season, with a sufficiently high air temperature and not strong humidity.

( 2 marks, average 2.

5 of 5 )