Sawn treated timber 150mm (W) x 47mm (T) x 4200mm (L). All of our structural sawn and treated timber is kiln dried to reduce shrinkage, pressure treated with Tanalith E to stop rot, regularised to ensure a consistent size, and has eased edges to make manual handling of the timber easier. The sawn timber is strength graded as C24 to comply with BS 5268. The grade will be stamped on the timber usually on the ends. Please be aware that the finished size of the sawn timber will be 5mm or so less than the nominal size quoted.