Products > Kooltherm > Kooltherm K5 External Wall Board > Overview Kooltherm K5 External Wall Board External insulation for masonry walls Kingspan Kooltherm K5 External Wall Board Properties Download PDF Thermal conductivity (insulant thickness) 0.023 W/m.K (15-24 mm) 0.021 W/m.K ( 25–44 mm) 0.020 W/m.K ( ≥ 45 mm) Facings Glass tissue Core Premium performance rigid thermoset modified resin insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP). Board size 1.2 x 0.6 m Agrément approved under certified systems.