In cases where external insulation of the facade wall is not possible (e.g. existing buildings with protected facade view or historic building, walls in direct contact with the ground etc.), the RAVATHERM™ XPS 300 WB closed-cell insulation can be placed on the internal walls as well.
As the insulation is applied on the warm, inner side, the wall structure will be exposed to more severe temperature changes arising from winter/summer temperature changes.
Because of the above reasons, the installation of max. 3 to 4 cm closed-cell polystyrene foam thermal insulation is recommended.
Special attention should be paid also to thermal bridges along the adjoining structures (internal walls, floors and slabs). The condensation risk must be checked carefully with respect to vapour migration in the entire order of layers considering the higher vapour load of rooms with high relative air humidity.
IMPROVING COMFORT CONDITIONS
The greatest advantage of inner-side thermal insulation is much higher comfort in the room after installation. The surface temperature of thermally insulated walls can increase even by several centigrades providing a pleasant thermal comfort for those in the room.
DECREASED MOLD-FORMATION RISK
The increase of the surface temperature involves the decrease of the risk of condensation. If there is no condensation and relative humidity on the internal surface of the wall does not reach 75% persistently, the likelihood of mold-growth will also decrease making the room healthier.
Regular ventilation is important even in internally insulated rooms , because only a little part of the vapour leaves through the boundary surfaces.
The rough, well-adhering surface of RAVATHERM™ XPS 300 WB boards creates a suitable basis for plastered or adhesive-bonded internal finishes (gypsum board, ceramic tiles etc.).
IF IT IS IMPOSSIBLE FROM THE OUTSIDE
When existing buildings are refurbished, it is not always possible to install thermal insulation on the external plane of the façade, especially when the original façade or its nature needs to be preserved.
For the subsequent thermal insulation of basement perimeter walls, application on the inner side is often the only possibility to improve thermal protection.
TEMPORARILY USED BUILDINGS
In the case of buildings or premises that are used only temporarily and not heated permanently, there are practical advantages of thermal insulation on the inner side, since there is no need to heat up the wall and slab structures with high heat storage capacity. In this way, the room can be heated up faster and using less energy.
CONSULT AN EXPERT
For designing thermal insulation for the inner side of an elevation wall, accurate knowledge of the existing uninsulated wall structure is a must. Thermal insulation will be installed on the internal side of the wall structure, so the winter temperature of the wall which is insulated from heated spaces and exposed to the temperature variations of the outside space will decrease as compared to the uninsulated status, and there is a higher risk of possible freezing. This is why inner-side thermal insulation can be applied in the case of walling made of frost-resistant materials in the entire cross-section.
VAPOUR CONTROL, VENTILATION
In most inner-side thermal insulation solutions, the design of internal vapour control, professional installation and the protection of vapour control layer(s) in case of building operation is inevitable. Thanks to the high vapour diffusion resistance of RAVATHERMTM XPS 300 WB, the thermal insulation can be used without a separate vapour barrier layer. If the thermal insulation is installed with close connection, with a closed gap, the risk of condensation and mold-growing behind the thermal insulation will remain low.
THERMAL INSULATION TURNED OVER
In order to prevent the “migration” of the condensation zone from the corner to the ceiling or floor, thermal bridge effects need to be reduced and the thermal insulation should be turned over also to the adjoining structures (ceiling, partition etc.) in a 30 to 50 cm width where necessary.
In consideration of the above, the STYROFOAM™ XPS thermal insulation boards provide a durable and efficient solution also as the inner-side thermal insulation of walls.