OSB (also knows as Oriented Strand Board or waterproof chipboard) is a type of engineered wood which is formed by adding adhesives & then compressing layers of wood strands in specific orientations similar to plywood. Our OSB sheet material features: Waterproof OBS is stronger than other plywood & chipboard options Designed for a whole range of indoor & outdoor building, construction & DIY applications but most commonly used for walls, flooring & roof decking Our OSB/ Waterproof Chipboard Sheet Material is sold sized: 8' x 4' (2.4 m x 1.2 m) Sizes available: Full sheet - 8 foot x 4 foot (2.4 m x 1.2 m) Half sheet - 4 foot x 4 foot (1.2m x 1.2m) Per Foot - 1 foot x 1 foot (0.3m x 0.3m) Examples: 1m x 1m (3 foot x 3 foot) - Workout square measurement and round up which in this case would be approximately 10 square foot (1m square) Select quantity "Per foot" 9 times. At checkout specify 1m x 1m. Or select Half Sheet and enter 1m x 1m at the checkout. If you need assistance with putting your order together then contact us and we will assist you.