Our Treated Timber Decking is manufactured from high-quality imported softwood. It is the perfect addition to any outdoor space, as an alternative to grass or paving. Please Note: All given sizes are nominal, which will differ from the final size. The nominal size is when the timber is rough sawn and unprocessed. However, processing is performed to create the attractive smooth finish that most of us look for, particularly in decking; however, this will result in a smaller finished size.