Grooved & Smooth Treated Softwood Decking Boards

Quick answer: Treated softwood decking boards are pressure treated, reversible timber boards used for garden decking, patios, seating areas and outdoor living spaces. These boards have a smooth face and a grooved face, with a nominal size of 125mm x 32mm and a finished profile of approximately 120mm x 28mm. What is this used for? These treated softwood decking boards are used to create outdoor decked areas for gardens, patios, seating areas, sheds, summerhouses and other outdoor living spaces. They can also be used as replacement boards for existing timber decking where the size and profile are suitable. The boards are kiln dried and pressure treated for exterior use, making them a practical choice for domestic and trade decking projects where a clean, traditional timber deck finish is wanted. Is this the right decking board for your project? Choose treated softwood decking boards if you want a cost-effective timber decking surface for a garden, patio, seating area or outdoor walkway. They are a good option where you want real timber, easy cutting, straightforward fixing and a traditional outdoor deck appearance. These boards are for the deck surface only. A good deck also needs a suitable subframe, correct joist spacing, adequate support, drainage, ventilation and the right fixings. If you are planning a new deck, use the Decking Joist Calculator before ordering your frame materials. What size are these decking boards? These boards are sold as 125mm x 32mm decking boards. After machining, the finished profile is approximately 120mm x 28mm. Available lengths include 2.4m, 3.6m, 3.9m, 4.2m and 4.8m. Choose the length that gives the best layout with the fewest joins, cuts and wasted offcuts. Size note: Imperial sizes are provided as a familiar reference only. All timber is sold in metric measurements, so please use the listed metric size when ordering or checking suitability for your project. Smooth side or grooved side? These decking boards are reversible, with one smooth face and one grooved face. This gives you flexibility over the finished look of your deck. Some people choose the grooved side for a traditional decked appearance, while others prefer the cleaner look of the smooth side. Whichever face you choose, the boards must still be fitted correctly with suitable spacing, drainage and ventilation. How many boards do you need? The number of boards depends on the deck size, board direction, board spacing, wastage and whether you are using any picture-frame borders or angled layouts. As a simple starting point, allow for the finished board width, spacing between boards and a sensible waste allowance. More decorative layouts usually need more boards and more careful cutting than a straight board layout. Key features Pressure treated softwood: Treated for exterior decking and outdoor timber use. Kiln dried: Helps reduce movement during installation compared with wetter timber. Reversible profile: Choose between a smooth face and a grooved face depending on the finish you prefer. Finished profile: Sold as 125mm x 32mm, with an approximate finished size of 120mm x 28mm. Multiple lengths available: Choose from 2.4m, 3.6m, 3.9m, 4.2m and 4.8m lengths. Easy to cut and fix: Suitable for standard woodworking tools and exterior-grade decking fixings. Things to check before ordering Deck size: Measure the finished deck area carefully before calculating board quantities. Finished board size: These boards finish at approximately 120mm x 28mm after machining. Board length: Choose lengths that suit your deck layout and reduce unnecessary joins where possible. Subframe: Make sure your joists, supports and posts are suitable for the deck size, height and loading. Joist spacing: Use the Decking Joist Calculator to help plan joist centres and support layout for common domestic decking frames. Spacing between boards: Allow appropriate gaps between boards for drainage and normal timber movement. Ventilation: Decking should be installed with adequate airflow beneath the boards. Fixings: Use suitable decking screws or exterior-grade decking fixings. Cut ends: Re-treat freshly cut ends where possible after cutting. Maintenance: Timber decking will weather outdoors and should be cleaned and maintained as needed. Complete the job For a full deck build, you may also need suitable deck joists, support posts, weed membrane, exterior-grade decking screws and other subframe materials. Use the Decking Joist Calculator to help plan joist centres, support layout and timber quantities for common domestic decking frames. To compare related decking products, view the full Decking Boards collection. For wider outdoor timber projects, browse Fencing, Decking & Landscaping.