Regardless of whether
the building has a basement or not, it is necessary to insulate the
foundations. In an energy-saving
house, not only cellar walls, but also foundation walls must be insulated, even
when they are built of materials that manufacturers declare that they have good
thermal insulation.
In most cases, the
foundations are warming from the outside. Thermal
insulation is also placed in the layered foundation wall - between the
supporting and the covering layer. Foundation
walls should be insulated at least 1
m below the ground level - in
practice, they are warmed up to the level of foundation foundations, similar to
basement walls, and at least 30
cm above ground level. There are no requirements regarding
thermal insulation of foundation walls in the current regulations, but in an energy-saving house it is
recommended to insulate
foundation walls from the outside
and inside of buildings, as well as foundations.
Materials for thermal
insulation of foundations
Materials used for
thermal insulation of foundations should have the lowest possible thermal
conductivity, have high compressive strength, be resistant to moisture and
biological corrosion, but also allow drying of concrete foundations and ensure
drainage of rainwater.
Extruded XPS polystyrene
boards have less absorbability
than styrofoam, so they can be used even at high groundwater levels.XPS boards
also have a favorable heat transfer coefficient λ (approximately 0.027 W / (m · K), it is also more resistant to
mechanical damage) The boards can be laid directly on waterproof insulation
without the need for a protective layer. organic solvents, therefore for the
boards to be bonded, the same preparations should be used as in the case of
polystyrene (which does not contain organic solvents). Sufficiently insulated
foundation walls have a layer thickness of 4
cm .
Expanded polystyrene EPS
boards - for insulation of one- and two-layer walls, boards with increased
compressive strength are used, eg EPS class above 100, because the adjoining
ground exerts a lot of pressure on the building. They are glued to the wall with
water-based emulsions of asphalt and rubber, which additionally insulate the
wall against moisture. From the
outside, the expanded polystyrene should be protected with hydroinsulation foil
or fiberglass mesh, embedded in the adhesive mortar, which will protect the
material against rodents. In the
three-layer wall, the thermal insulation layer is embedded with a clamping wall
made of blocks or bricks. Warning! Styrofoam should not be used at a high
level of groundwater - although its water absorption is small, it should not be
exposed to constant contact with water. For
insulating foundations, a 10 cm layer of polystyrene is usually used .
EPS and XPS grooved
plates - facilitate drainage of water, eg. Steinodur, which have a specially
finished surface - on one side the plate has drainage grooves for draining
groundwater into the drainage system, on the other pressed 2 x 2 mm grooves , forming a fine square mesh ensuring
excellent adhesion of plasters and adhesives. Each
panel has a rim on the edge, giving a secure and tight connection, which does
not allow thermal bridging. The
grooved plates are laid with grooves towards the ground. Foundation walls can also be insulated
with grooved panels laminated geotextile, which acts as a filter and prevents
the clogging of grooves with ground clods and pebbles.
Hard PIR polyurethane
foam boards - characterized by high thermal insulation as well as resistance to
mechanical damage.
Stone wool slabs -
special hydrophobic boards are used only for three-layer foundation walls, when
it is separated from the ground by a curtain wall.
