Rockwool’s Dual Density Insulation Range

My work in retrofit has largely focussed on post-war buildings, particularly high-rise, where external wall insulation is a large element in our ‘armoury’. For that reason I would like to nominate Rockwool’s Dual Density insulation range as my first ‘game-changer’. Made from spun basalt rock, it ticks every box: very low thermal conductivity at 0.036 W/mK; excellent acoustic properties, vapour open; and perhaps most importantly of all, has a Euroclass fire rating of A1 non-combustible. From an installation point of view, the slabs are perfectly engineered, with a denser outer ‘crust’ that provides a robust fixing surface for the mechanical washer head fixings and a more flexible face that will fit tightly to uneven substrates. When slab are butt-jointed, they can be pushed together to ensure the fibres mesh together avoiding the thermal bypass risks associated with inflexible rigid insulations. The slabs now come in a rain screen version with a black surface for aesthetic reasons. Finally, the slabs use relatively low embodied energy compared to plastic foam equivalents and can be recycled back into new insulation at the end of life.