Treated Timber

Timber must be graded if it is to be used in internal structural applications as stipulated by building regulations. Timber is graded to either C16 or C24. Here all the structural properties of the timber are quantified. Eg Species, Knot Size and Type, Slope of Grain, Tightness of grain, Compression Wood, Rot etc. C24 grade can only be achieved by imported timber. Homegrown timber from UK sawmills will make C16 only and so will have reduced span capability. At Bennetts Timber we stock C24 regularised timbers.

Nominal size is the actual size of timber that the board is machined out of, in other words the finished product will have a smaller finished size than the nominal size. For example 47mm x 100mm C24 regularised graded is the nominal size, the finished size is 45mm x 95mm or thereabouts.

Although the sawing process is a lot more accurate than it was some years ago, by regularising the timber the end user can be sure that in whatever application, each piece will have consistent and "regular' size. It is also more visually appealing as it usually has curved edges, rather than straight.