Decoboard by LAMBDABOARD laminated polyisocyanurate core board with a minimum core density of 34kg/m³, minimum thickness of ____ mm; in widths of 300mm or 900mm with a _____(Km²/W) R-Value. Finish shall be White Mineral and Mineral Natural laminated on each side with a White Mineral side displaying grooves. Lambdaboard to be mechanically fastened using concealed clip into battens placed at 900mm centres. Side lap shall be interlocking joint using the Tongue and groove lap. Finished with one or two coats of high-quality acrylic paint, in accordance with manufactures specification.