Durable and waterproof ground frost insulation
Ground frost insulation
Ground frost insulation is one of the fundamentals of construction. Ground frost insulation must work reliably for at least 50 years, and replacing insulation after building is expensive and difficult. Reliability is therefore the most important property of ground frost insulation material. All products intended to be used as ground frost insulation materials must have proven freeze-thaw resistance. The test corresponds to the conditions the material will be subjected to in the ground (taking safety coefficients into account).
In passive and zero-energy houses, the amount of waste heat leaking from the base is so small that the thickness of the ground frost insulation layer must be increased by 50% in straight walls sections and by up to 100% in corners. An alternative to this is to make the ground frost insulation layer wider by installing, for example, 3 boards parallel to each other, resulting in a ground frost insulation width of 1.8 metres.
Completely homogenous and closed cell structure
Finnfoam is very durable – also when the conditions become demanding during events such as flooding or malfunctions of the building's drainage system. Finnfoam's completely homogenous and closed cell structure prevents penetration by tree roots, water or soil. Finnfoam ground frost insulation materials require no protective plastic sheeting or drainage systems to function properly. Sub-surface drains, however, are an important factor with considerable impact on the functioning and durability of other structural elements, and must never be omitted.
Finnfoam is waterproof
Ground frost insulation materials must always remain dry. Ground frost insulation that has absorbed water no longer functions as insulation material and may break when it freezes. This is why all ground frost insulation materials must be tested to establish their freeze-thaw resistance. Finnfoam's completely homogenous and closed cell structure does not become waterlogged even when submerged for extended periods of times or periodically frozen. The results of the long-term submersion test can be viewed below.
Finnfoam lasts without compacting
Ground frost insulation installed horizontally is often subjected to further above-ground loads in addition to the pressure of the soil above it. These are usually point-type loads such as vehicle traffic and rocks used for landscaping purposes. The impact of these point loads can be distributed over a greater area with a topsoil layer of 30 cm or more laid on top of the insulation material. The best ground frost insulation, however, is achieved with the insulation material installed near the surface of the ground.
Due to Finnfoam's excellent compression strength, the insulation can also be installed beneath the foundation of a building. Finnfoam also withstands the weight of heavy construction machinery. In all applications, it is always important to select the product with the right compression strength. The F-300, for example, is a good choice for areas with regular vehicle traffic, whilst for a lorry terminal the F-400 is ideal.
Finnfoam insulation boards are designed to withstand the loads generated during the pouring of concrete when building a split socle. Finnfoam insulation boards can be used as socle insulation material and may be used simultaneously as a concrete mould to improve productivity. The smooth-surfaced Finnfoam can be removed intact after the concrete pouring, as it does not stick to the concrete. If the insulation boards are intended to be attached to the concrete, the surface of the boards must be roughened or grooved slightly. Finnfoam insulation boards may also be installed on top of the socle later using remodelling mortar. Finnfoam insulation boards can be coated using single-layer plastering following the plaster manufacturer’s instructions.
Frost heave compensation using a transition wedge
The earth generates heat when it freezes under the insulation material. The amount of heat increases in proportion to surface area A. The greater the surface area, the more heat is generated under the insulation. In terms of ground frost protection, it is therefore best to install the insulation as close to the surface possible. A transition wedge can be used to even out ground frost elevations, but it also increases the amount of heat released during the freezing process.