We recommend that you seek advice from your architect, designer, energy assessor etc. to determine the appropriate insulation thickness. If you already know the desired performance, you can use our free U-value calculator or look up the required R-value and corresponding thickness in the technical datasheet.
The cleanest energy for heating and cooling, is the energy you do not have to use. That is why we recommend to insulate a flat roof to a higher standard than the minimum requirement. We recommend a minimum of 45 mm Deck-VQ® (RD = 5,00 m²K/W) for renovation and 60 mm (RD = 7,50 m²K/W) for new build.