C16 Treated Timber is a p ressure-treated preservatives are forced into the timber to protect against fungal & insect attack enhancing protection. Treating timber wood helps extend the life of this construction material, reducing the levels of upkeep and repair needed. Stress graded to C16 specification for structural applications. This timber is avialble in the following sizes: 2400mm 3000mm 3600mm 4200mm 4800mm Contact us today. PLEASE NOTE Regularised (consistent dimensions) by planing all round with eased/rounded corners for comfortable handling. Our regularised carcassing finishes 2mm off nominal thickness and 5mm off nominal width.