External walls - together with windows - are generally the largest cooling surface of the building. Therefore the insulation of these walls can significantly reduce the heat loss and increase the comfort. From building physics point of view the optimal solution is to install the insulation on the external face of the building envelope: this way the risk of interstitial condensation is minimized, the existing structural walls also get thermal protection and the heat storage capacity of the massive walls are utilised.
However, in certain cases the external application of an insulation layer is not possible, or the internal use of an insulation layer has more benefits. When upgrading existing buildings it is not always possible to apply the insulation externally, especially if the outside appearance of the façade must be retained. In the case of existing walls with direct contact to the ground, the internal wall insulation is often the only way to improve thermal insulation. Internal insulation has significant advantages in rooms for temporary use, not heated permanently: those can be heated with minimum energy consumption.
The use of SHAPEMATE™ GREC-A insulation boards offer long-term, efficient insulation. The planed or profiled surface creates a suitable basis for plastered or adhered finishing's (gypsum board, ceramic tiles).The correct design of an internally insulated façade wall always needs exact information about the existing, uninsulated wall construction. Since the insulation is applied on the inner, warm side, the wall structure will be exposed to more severe temperature changes. The brickwork, stonework or concrete wall should be frost resistant in its entire thickness as the internal insulation will lower the temperature in the wall structure, with potentially greater risk during freeze/thaw cycles.
With internal insulation, thermal bridges should get increased attention. Insulating the adjoining structures (walls, floor slabs perpendicular to the facade walls) can help to reduce the negative effects.
SHAPEMATE GREC-A boards have relatively high vapour diffusion resistance: in the case of correct design and installation generally there is no need for an additional vapour barrier. However, the condensation risk must be checked carefully, especially in rooms with high relative air humidity. The internally insulated rooms also require careful attention to regular and efficient ventilation.
The insulation boards are glued with cement based adhesive mortar by "spot-mop" or full surface to the wall and/or fixed mechanically. The surface is finished with traditional thick plaster or gypsum board. The joints between the boards and between other construction parts must be closed to prevent risk of condensation. When installing plasterboards, joints must be finished according to the manufacturer's instructions.