...

Insulation of the foundation with extruded polystyrene foam

Insulating a foundation with extruded polystyrene foam is a great way to protect it from moisture, mold, heat, and cold. It not only prevents damage from ambient temperatures, but also makes insulated floors, walls, and crawlspaces. It is a lightweight and easy-to-install solution with consistent thermal performance across the entire construction. Moreover, it provides excellent sound deadening properties and helps reduce energy costs, while its closed-cell structure provides additional rigidity and water resistance. This makes extruded polystyrene foam an effective and affordable insulation material for foundations.

Recommendation points



Up to 20% of heat loss in a house occurs due to an uninsulated foundation. Freezing of the soil affects its integrity. It is not difficult to insulate the base of the house with extruded polystyrene foam, you only need to adhere to some rules and the technological process.

Insulation of the foundation with extruded polystyrene foam

Types of expanded polystyrene for the foundation

Extruded polystyrene foam and polystyrene foam belong to the same group of heaters. Installation methods are no different. Insulation boards have different technological characteristics and differ in price.

Foam plastic is produced in the form of plates of 500ร—1000, 1000ร—1000 and 1000ร—2000 mm. The thickness of the foam plates for insulation is from 20 to 100 mm. When choosing a foam, its density is also taken into account. The porous structure of the foam tends to absorb moisture. After installing the insulation plates, additional treatment with waterproofing mastics or installation of a roll-type hydro-barrier will be required. The strength of foam boards is much lower than that of extruded polystyrene foam.

Insulation of the foundation with extruded polystyrene foam

An inexpensive and practical material for warming the foundation is extruded polystyrene foam. Low price, ease of processing and low thermal conductivity distinguish it favorably among similar types of insulation material. EPPS has an extremely low vapor permeability coefficient. It does not allow moisture to pass through and is suitable for insulating any kind of foundation. Extruded polystyrene foam boards are produced from 10 to 120 mm thick. Some manufacturers make an L-shaped sample on insulation plates. When installing such plates, cold bridges are eliminated.

Insulation of the foundation with extruded polystyrene foam

Insulation for the foundation must have a low thermal conductivity, not absorb moisture and be durable. It is not a violation of the insulation technology and the combination of various types of insulation.

Tools and materials for insulation work

For work on warming the foundation with expanded polystyrene, you will need:

  1. Hammer drill or hammer drill.
  2. Concrete turbo grinder with cutting disc.
  3. Drills for concrete or drill. Mixer for mixing glue and plaster.
  4. Flat spatulas for plaster and comb-type spatula for glue.
  5. Hammer, knife, tape measure and level.

Insulation of the foundation with extruded polystyrene foam

Of the materials for warming the foundation, you will need:

  1. Insulation material (EPS or foam).
  2. Expanded polystyrene glue or glue mastic.
  3. Plastic disc dowels. The quantity is calculated โ€“ 5 pcs. 1 m2, and the caliber depending on the thickness of the expanded polystyrene. The working part must enter the concrete of the foundation by 2/3 of the length.
  4. Dry mix for external plaster.
  5. Reinforced plastic mesh with a density of 140-160 g / m22 with cells 5ร—5 mm.
  6. Deeply penetrating plaster primer.

Preparatory work

Warming of the foundation is carried out immediately after its construction and removal of the formwork. When insulating an already erected house, a trench is dug around the entire perimeter to the base of the foundation, but not less than the level of freezing of the soil. The width of the trench is made sufficient for installation work. The exposed walls of the foundation are cleaned of soil and dried. The vertical walls of the foundation are aligned. The protruding areas are cut off with a grinder, and the depressions are leveled with cement mortar.

Insulation of the foundation with extruded polystyrene foam

The vertical plane of the foundation is treated with waterproofing bitumen mastic or pasted over with a waterproof material. Sometimes roofing material or rubemast are used for this..

Insulation of the foundation with expanded polystyrene

Plates of extruded polystyrene foam are attached over the waterproofing using bitumen-polymer mastics or special glue. Dot strokes of glue are applied along the perimeter of the insulation sheet and in the center. On one sheet of 1ร—1 meter, 16-18 strokes are evenly distributed with a plastering trowel. On the lower edge of the slab in contact with the ground, the adhesive mixture is leveled in a continuous line with a comb trowel. This is necessary to prevent the penetration of groundwater under the insulation.

Insulation of the foundation with extruded polystyrene foam

Expanded polystyrene plates begin to be installed from the bottom corner of the foundation. They are pressed tightly against the vertical plane of the foundation for several minutes. With a great depth of the foundation, expanded polystyrene sheets are installed with a horizontal offset. In the lower part of the foundation, the insulation slabs are not fixed with dowels. When backfilling the trench, the soil will reliably press the extruded polystyrene foam to the foundation.

When installing the last row of polystyrene foam boards, the upper edge is coated with a continuous line of glue. This is necessary to prevent rainwater from getting under the insulation. Sometimes polystyrene foam inserts are installed at the junction. Outwardly, they look like baguette cornices and have a triangular profile from the end..

Insulation of the foundation with extruded polystyrene foam

Above the blind area, the slabs are fixed with plastic dowels. On a sheet of 1 m2 use 4 dowels in the corners and one in the center. When installing boards on an uneven surface, gaps and crevices inevitably appear. These places are coated with mastic or glue. Wide gaps are well eliminated with frost-resistant polyurethane foam.

Insulation of the foundation with extruded polystyrene foam

The entire above-ground surface of the insulation is tightened with a reinforced fiberglass mesh and plastered with a thin layer of 3โ€“8 mm. The dried plaster layer is covered with a deeply penetrating primer.

Insulation of the foundation with extruded polystyrene foam

The final stage

At the final stage, the trench is filled with soil and sand with simultaneous ramming. Before reaching 15โ€“20 cm to the soil level, a sand and gravel mixture is poured for arranging the blind area. In areas with strongly freezing soils, additional insulation of the blind area is performed.

Insulation of the foundation with extruded polystyrene foam

Rate the article
( No ratings yet )
Recommender Great
Tips on any topic from experts
Comments: 1
  1. Riley Campbell

    What are the advantages of using extruded polystyrene foam for foundation insulation? How does it compare to other insulation materials in terms of insulating properties, durability, and cost-effectiveness? Are there any specific installation guidelines or considerations to keep in mind when using this type of insulation for foundation applications?

    Reply
Add comments