With the EU Green Homes Directive, millions of historic masonry buildings must be energy-retrofitted. Unable to install external insulation, building physics collides with the danger of interstitial condensation. The Calcium Silicate board is the only engineered answer to insulating the interior without causing rot.
Insulating an old brick wall from the inside with polystyrene or polyurethane creates a perfect trap. Moisture in the old wall can no longer dry towards the room interior. This causes inevitable liquid condensation between the insulator and the cold masonry, triggering devastating black mould and plaster disintegration.
Calcium Silicate is a massive micro-porous board (over 90% of its volume is interconnected micro-pores). It does not block vapour, it manages it (diffusion-open insulation). During humidity peaks, the board acts as a hydraulic buffer, rapidly absorbing condensation into its micro-capillaries and spreading it over a large area. As soon as the air dries, the board breathes, releasing moisture as invisible vapour.
Standards
European and international references applicable.
Physical properties
Usage environment
FULL-BED BONDING: there must be no air behind the panel. If adhesive is applied in dabs (as in EPS external insulation), warm air infiltrates the gap and condenses on the cold wall. Silicate adhesive must be spread over the entire slab (100% full-bed). NO GYPSUM: gypsum-based plaster or acrylic paints close the pores, blocking evaporation. Use only silicate or natural hydraulic lime (NHL) mortars.