Approx. 20 % of the total heat loss of a single family house can occur by not insulated cellar walls. In order to reduce energy consumption, achieve pleasant indoor climate and prevent surface condensation, the rooms being in direct contact with the soil should be provided with enhanced thermal insulation. Thermal insulation of unheated areas or unused basement/cellars can be useful, in order to prevent development of heat bridges at footings or to avoid undesirable condensation.
The RAVATHERM™ XPS 300 SL closed-cell polystyrene foam is an indispensable accessory for underground thermal insulation, because of the following benefits:
- closed-cell structure,
- excellent thermal insulation capability,
- high compressive strength
The permanent presence of moisture or pressure caused by groundwater or soil bodies should not decrease the efficiency of thermal insulation products integrated in building structures being in direct contact with the soil. Owing to their closed-cell structure resulting from the manufacturing technology, the RAVATHERM™ XPS extruded polystyrene foam plates reserve their high thermal insulation values even in the presence of permanent presence of moisture (soil vapors/moisture, groundwater or stratum water) and under intensive mechanical load. The professionally installed thermal insulation shall provide long-term and reliable protection.
From building physics aspects, the thermal insulation fixed to the cold external surfaces shall prevent moisture condensation on indoor surfaces or in the building structure.
The efficiency of the external cellar wall insulation should not be reduced by long-term exposure to moisture, ground-water and soil-pressure.
The closed-cell structure, excellent thermal insulation properties, waterproofness and high compressive strength of the RAVATHERM™ XPS 300 SL permits to install the product as the outermost layer of wall structure, even in direct contact with the soil. Apart from numerous advantages, the heat storing capacity of the structure will be preserved behind the outside thermal insulation.
THERMAL INSULATION AND PROTECTION OF THE INSULATION
When glued to the waterproofing surface, RAVATHERM XPS 300 SL provides the structure (and also the waterproofing surface) with thermal and mechanical protection.
RAVATHERM XPS 300 SL can be applied also in the presence of groundwater (assuming waterproofing insulation), in addition to the protection from soil moisture.
WARNING! The XPS is not, in itself, a waterproofing material!
THERMAL INSULATION AT GROUND MOISTURE
RAVATHERM XPS insulation boards are simply bonded with INSTA-STIK polyurethane solvent-free adhesive to the external face of the waterproofing membrane or the waterproof reinforced concrete cellar wall. To wall surface the adhesive should be bead-applied (min. 3 strips per board). The insulation boards are installed with tight joints and in brick pattern, either horizontal or vertical position on the cellar wall. RAVATHERM XPS boards must “stand” on a firm base area at the foot (for example foundation step), having a support base to avoid the sliding during compacting the backfill later.
INSULATION IN GROUND-WATER
RAVATHERM XPS boards can be used also when exposed to permanent pressure of ground-water. The entire surface of the insulation boards must be adhered with solvent free cold bitumen adhesive to the waterproofing membrane or watertight reinforced concrete wall in order to prevent water standing between the insulation layer and the membrane or concrete wall.
The extruded polystyrene plates are non biodegradable products. Therefore, their use do not impose environmental risk to the integrity of soils and the biological composition of the soil and live waters.