Products > Kooltherm > Kooltherm K108 Cavity Board (Lower Lambda) > Overview Kooltherm K108 Cavity Board (Lower Lambda) Kingspan Kooltherm K108 Cavity Board is a premium performance lower lambda insulation with a rigid thermoset fibre-free phenolic core. It is faced on both sides with a low emissivity composite foil facing and is used in partially filled cavity walls. Kingspan Kooltherm K108 Cavity Board Properties Download PDF Thermal conductivity 0.018 W/m.K Facings Composite foil Core Premium performance lower-lambda rigid thermoset phenolic insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP). Board size 1.2 x 0.45 m U-value Calculations for Cavity Walls NBS Product Specification Looking for a slimmer cavity? See Kingspan Kooltherm K106 Cavity Board (Lower Lambda 10mm Cavity).