Insulation of the foundation outside

In the operation of any building up to 1/5 of the heat loss falls on its foundation - the foundation. At the same time, owners of private homes often neglect the foundation warming, especially if the basement is not used in the house. And completely in vain - high-quality insulation of the foundation from the outside helps reduce heat losses, reduce humidity in the basement, extend the life of the foundation and walls.

Why should the foundation be insulated from the outside?

Many believe that it is easier to insulate the base from the inside, and at the same time commit a gross error. They isolate the basement from low temperatures, but at the same time they do not save the material from which the foundation is made from the destructive effects of water and cold: in the foundation that has absorbed moisture, microcracks form gradually, and sooner or later the foundation begins to crumble, loses its strengthand reliability.

Insulation of the foundation from the outside allows not only to protect the lower part of the house from moisture, but also to protect the basement walls from freezing. The dew point is shifted towards the insulation, which is much more resistant to the harmful effects of moisture and lower temperatures than concrete.

Ways of foundation warming

There are several ways to warm the foundation from the outside: by filling with gravel, using various insulation sheets, and foam polyurethane foam sprayed onto the base of the plinth. All methods have their advantages and disadvantages, limiting the scope of their application.

For private construction, the most reliable and easy-to-perform method is the insulation of the foundation from the outside with polystyrene sheets. This material has several advantages:

• Strength and durability;
• Resistance to moisture;
• Easy mounting and mounting;
• Due to its increased strength, rodents are not damaged;
• It is easily lend itself to an external decorative finish;
• The material is easy to process, and the foundation can be insulated by hand;
• Due to the increased strength of the polystyrene plate, they take on a part of the load of the soil soils.
• The price of polystyrene is quite affordable.

Thermal insulation of the outside with polystyrene

Before starting work, it is necessary to perform calculations and determine the number and thickness of polystyrene plates. Typically, for the middle band, enough plates with a thickness of 5-8 cm In addition, you will need the following tools and materials:

• Rotary hammer with a drill. The length of the drill is not less than 15 cm, diameter - 10 mm;
• Building mixer and concrete mixer;
• Self-adhesive self-adhesive waterproofing on a polymer basis. You can use the coating, but without bitumen - the components of bituminous mastics destroy polystyrene;
• Primer for concrete;
• Adhesive for mounting polystyrene plates to the foundation;
• Dowels with poppet head for fixing polystyrene plates;
• Mounting foam;
• Reinforcing mesh;
• Cement-sand mortar;
• Gravel and coarse sand;
• Facing materials and appropriate glue.

The technology consists of several stages:

1. When building a new house, the basement will be insulated immediately after its erection and installation of the floor slabs of the basement. If it is planned to insulate the already built house, then the foundation must first be dug around the perimeter at least a meter wide. The depth of the trench should be such as to dig up the foundation to the very bottom.
2. The walls of the foundation must be dried, dirt, soil debris, dust and other impurities removed.
3. If the house stands on a site with a close groundwater table - the drainage is laid on the bottom of the trench: a layer of river sand and a geotextile are laid. On the geotextile lay a layer of gravel, a perforated pipe with a diameter of at least 10 cm, then they cover the pipe with gravel, wrap it with geotextiles and fill it with river sand. This drainage qualitatively removes moisture from the walls of the basement. Pipes need to be taken out to a collector well, located near the house.
4. The walls of the cap are covered with a latex-based primer. Primer fills all pores and cracks and provides good adhesion of waterproofing to the foundation.
5. Lay self-adhesive waterproofing, ironing it with a solid roller over the entire surface. Joints are additionally glued with a sealant.

• Polystyrene sheets are attached to the waterproofing with a special glue. The glue is applied to the sheet with an intermittent strip around the edges, retreating 1-2 cm, as well as several points along the remaining area of ​​the sheet.
• Apply a polystyrene slab to the prepared layer of waterproofing and strongly press. The next sheet is attached similarly to the overlap, with the joining of the sheets produced using a special groove at their joints.

• If the foundation has a significant height, and several rows of polystyrene slabs are required, the rows are staggered so that no large vertical seams are formed.
• After laying large gaps are frosted, shpaklyuyut glue or fill with sealant, so as not to form bridges of cold.

• It is not necessary to fasten sheets of polystyrene to the substrate at ground level, as when filling the ground will press them to the foundation.
• Backfill is produced by coarse-grained dry sand, along the top layer - with the addition of gravel. Gravel cushion will create a basis for warming the soil layer.
• Above the soil level, polystyrene slabs are fixed to the foundation with special dowels with a wide poppet cap. They are made of plastic and do not create cold bridges. To fix the drilling drill holes in the heater so that its depth of 5-7 cm went into the concrete. Dowels are hammered. Each plate is fastened to 4-5 anchors.

• . For finishing, the insulation is plastered with glue for finishing works. To make the layer of plaster strength use a reinforcing mesh for external work, applying it to freshly applied plaster and smoothing so that the surface of the mesh was completely recessed in the solution. The plaster dries 2-3 days.
• Do formwork under the plinth of plank timber, the width of the blind is not less than 60 cm. Under the plaster on the gravel-sand cushion, polystyrene plates, reinforcement mesh with a mesh of 10 cm are placed for additional insulation, then the concrete formwork is poured with concrete. About the blind area around the house read on our website.

• After drying of the blind, it is possible to start finishing the foundation with any decorative materials.

Correctly executed foundation insulation from the outside is not only reliable and durable, but also gives the house a finished and neat appearance, protects its walls from damage when punching the ground and provides a dry and warm basement.

Also read about the foundation warming yourself.