Sawn & Treated

Sawn and treated timber is timber that has been cut to size and pressure treated with preservative to improve its resistance to rot, decay and insect attack. It usually has a slightly rougher finish than planed timber, which makes it a practical choice for construction, outdoor framing, fencing, decking subframes and garden projects where appearance is less important than strength and durability.

Yes, treated timber is designed for outdoor use and is commonly used for fencing, sheds, pergolas, decking frames, garden structures and general exterior building work. The pressure treatment helps protect the timber from moisture and decay, but correct installation is still important. Try to avoid trapping water against the timber, allow airflow where possible, and check whether the timber is suitable for direct ground contact if it will be used in the soil.

Sawn and treated timber is used for jobs where strength, durability and value are more important than a smooth decorative finish. Common uses include decking joists, shed bases, fence rails, studwork, roof battens, garden framing, timber structures, landscaping work and general construction. It is a good choice for hidden structural areas, support frames and outdoor projects where untreated timber would be more likely to rot over time.  

C16 and C24 are structural strength grades. C16 timber is commonly used for general building work, stud walls, roof timbers, floor joists and many standard construction jobs. C24 is a stronger grade and is often chosen when higher load-bearing performance is needed, such as longer spans or more demanding structural work. If your project involves building control, load-bearing work or specific span requirements, check the plans or ask a qualified tradesperson before ordering.

Yes, treated sawn timber is commonly used for decking joists and decking subframes. It is usually the right choice because the frame sits outside and needs protection from moisture. For best results, keep the frame raised off the ground where possible, use suitable fixings, leave enough ventilation under the deck, and treat any cut ends before installation. The visible deck surface should normally be finished with proper decking boards rather than rough sawn timber.

Treated timber is much more resistant to rot than untreated timber, but it is not completely rot-proof. Its lifespan depends on where it is used, how wet it gets, whether it has airflow around it, and whether cut ends have been protected. Timber that stays constantly wet or is installed directly in the ground without the correct treatment class may still decay over time. Good installation and basic maintenance will help it last longer.

Yes. When treated timber is cut, drilled or notched, the newly exposed wood may not have the same level of protection as the original treated surfaces. Apply a suitable end-grain preservative to all cut ends before fitting the timber, especially for outdoor use. This is a simple step, but it helps protect the most vulnerable areas from moisture getting into the timber.

Yes, treated timber can usually be painted or stained, but it should be dry enough before applying any finish. Freshly treated timber can contain moisture, so it may need time to dry depending on storage conditions and the weather. Use an exterior-grade wood paint, stain or oil suitable for treated timber, and follow the manufacturer’s instructions. Staining or painting can improve the appearance of the timber and add another layer of weather protection.