Everything you need to know about range of timber
Type of Timber
- CLS Timber – “Canadian Lumber Size” or CLS is finished on all sides giving a smaller cross-section than traditional sawn timber. Originating in the Canadian market, hence the name it is mainly used for timber frame home construction and for internal and partition walls.
- Roofing Battens – these are smaller cross-section sawn timbers, produced mainly for roofing applications.
- Carcassing timber – these are the traditional sawn timber planks available in a wide range of cross-sections and widely available in lengths of up to 6m.
Where will the timber be used? If it is outside, you should use treated timber to avoid rot. Most sawn timber can be bought as tanalized. This means that it has been treated with Tanalith E wood preservative to give long term protection against both fungal decay and insect attack.
Finish
Regularised and eased edges? These finishes are both widely available. Regularisation refers to the trimming of all sides of the sawn timber so that every length is of a consistent size. This will generally take 5mm or so off the nominal or pre-machined size of the timber. Eased edges are rounded edges to help with the manual handling of the timber.
Size
As well as the more obvious length of sawn timber you require, you should also think about the cross-sectional size that you require. The larger the cross-section you choose the stronger the length of timber.
Strength Grade
Carcassing timber is usually available in two strength grades:
- C16 Grade - C16 graded sawn timber is the cost-effective option and will be good enough for most requirements if the correct spans are used. It is mainly used for roof and floor joists.
- C24 Grade - C24 graded sawn timber is a premium structural timber with fewer and smaller knots than C16 grade. It is stronger and therefore used where wider spans or higher loads are required. C24 grade can only be achieved by imported timber from areas where the climate forces a slow growth rate and hence a tight grain. Due to its faster growth rates, homegrown UK timber can only be graded as C16.
Sawn timber is widely available from builder’s and timber merchants and DIY stores as well as specialist distributors.
