Smartply MAX T&G4 OSB3 Flooring Board 18mm 2400 x 600mm is a high-performance structural tongue and groove OSB board designed for demanding load-bearing applications including flooring and roofing. Manufactured to OSB/3 grade, Smartply MAX is suitable for structural use in both dry and humid conditions. Its combination of strength, dimensional stability and moisture resistance makes this 18mm board particularly well suited to structural flooring, floor decking, roof decking and timber construction. Unlike standard square-edge OSB sheets, this board features a T&G4 profile, meaning all four edges are precision machined with tongue and groove joints. The interlocking edges help create secure joints between neighbouring boards, improving board alignment and helping distribute loads across the installed floor or roof deck.