Products > Kooltherm > Kooltherm K118 Insulated Plasterboard (Lower Lambda) > Overview Kooltherm K118 Insulated Plasterboard (Lower Lambda) Kingspan Kooltherm K118 Insulated Plasterboard is a premium performance, lower lambda internal wall insulation, with a fibre-free rigid thermoset phenolic core. It has a 12.5mm plasterboard bonded to its front surface and a composite foil based facing on its reverse surface. It is suitable for mechanically fixed or plaster dab / adhesive bonded dry-lining. Kingspan Kooltherm K118 Insulated Plasterboard Properties Download PDF Thermal conductivity 0.018 W/m.K Facings 12.5 mm plasterboard Core Premium performance lower lambda rigid thermoset phenolic insulation manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP). Reverse facing Composite foil Board size 1.2 x 2.4 m U-value Calculations for Internal Wall Insulation Please note that Kingspan Kooltherm K17 Insulated Plasterboard and Kingspan Kooltherm K18 Insulated Plasterboard are no longer available for specification.