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Timber Decking Range | Treated Decking Boards, Joists & Accessories

Build a durable and attractive outdoor space with our timber decking range, featuring high-quality, pressure-treated boards and all the essential components for a complete decking system. Whether you're constructing a garden patio, raised deck, or commercial platform, our treated timber is built to last.

Treated softwood decking boards – grooved and smooth profiles
Decking joists & subframes – UC4 treated for ground contact
Handrails, spindles & newel posts – perfect for balustrade systems
Decking screws & fixings – rust-resistant and long-lasting
✅ Available in a variety of lengths and sizes

Ideal for landscapers, joiners, and DIYers, our decking timber offers strength, style, and ease of installation. Nationwide delivery available on all decking supplies.

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100mm x 47mm (4"x2") joist, square sawn

Alter Supplies
Original price £10.70 - Original price £14.28
Original price £10.70 - Original price £14.28
Original price £10.70
£8.64 - £11.52
£8.64 - £11.52
Current price £8.64
In stock

100mm x 47mm (4"x2") Joist, Square Sawn Enhance your construction projects with our durable 100mm x 47mm joists, available in various lengths ...

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Original price £10.70 - Original price £14.28
Original price £10.70 - Original price £14.28
Original price £10.70
£8.64 - £11.52
£8.64 - £11.52
Current price £8.64
Save up to 19% Save %

Redwood Decking Treated 145mm x 28mm - 3.6m, 4.8m, 5.4m lengths

Alter Supplies
Original price £10.73 - Original price £15.60
Original price
£10.73 - £15.60
£10.73 - £15.60
Current price £10.73
In stock

Upgrade your outdoor space with our high-quality Redwood Decking. Made from treated redwood, it is durable and resistant to rot and decay. Availab...

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Original price £10.73 - Original price £15.60
Original price
£10.73 - £15.60
£10.73 - £15.60
Current price £10.73

Regularised 125 x 47 (5 x 2) Joist KD C24 in 4.8m & 3.6m

Alter Supplies
Original price £17.90
Original price £17.90 - Original price £17.90
Original price £17.90
£10.54 - £13.70
£10.54 - £13.70
Current price £10.54
In stock

125mm x 47mm Regularised C24 joist @ 4.8m & 3.6m long, pressure treated green, dressed, kiln dried. Used for general construction purposes or d...

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Original price £17.90
Original price £17.90 - Original price £17.90
Original price £17.90
£10.54 - £13.70
£10.54 - £13.70
Current price £10.54
Save up to 41% Save %

150mm x 47mm (6"x2") Joist, square sawn

Alter Supplies
Original price £16.07
Original price £16.07 - Original price £16.48
Original price £16.07
£12.36 - £16.48
£12.36 - £16.48
Current price £12.36
In stock

150mm x 47mm (6"x2") Joist, square sawn Enhance your construction projects with our 150mm x 47mm (6"x2") Joist, pressure treated in an att...

View full details
Original price £16.07
Original price £16.07 - Original price £16.48
Original price £16.07
£12.36 - £16.48
£12.36 - £16.48
Current price £12.36
Save up to 23% Save %

1.25M x 82 x 82mm Redwood Chamfered Decking Post Newel

Alter supplies
Original price £13.14 - Original price £13.14
Original price
£13.14
£13.14 - £13.14
Current price £13.14
In stock

1.25M x 82 x 82mm Redwood Chamfered Decking Post Newel Enhance your outdoor space with the 1.25M x 82 x 82mm Redwood Chamfered Decking Post...

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Original price £13.14 - Original price £13.14
Original price
£13.14
£13.14 - £13.14
Current price £13.14

Redwood Decking Spindle R4A Treated

Alter Supplies
Original price £2.28 - Original price £2.28
Original price
£2.28
£2.28 - £2.28
Current price £2.28
In stock

42*42*900mm Redwood Decking Spindle R4A Treated

Original price £2.28 - Original price £2.28
Original price
£2.28
£2.28 - £2.28
Current price £2.28

Redwood Decking Baserail Treated 4.2 x 78 x 38mm

Alter Supplies
Original price £12.24 - Original price £12.24
Original price
£12.24
£12.24 - £12.24
Current price £12.24
In stock

4.2M x 78 x 38mm Redwood Decking Baserail Treated

Original price £12.24 - Original price £12.24
Original price
£12.24
£12.24 - £12.24
Current price £12.24

Redwood Decking Handrail Treated 4.2 x 75 x 33mm

Alter Supplies
Original price £12.24 - Original price £12.24
Original price
£12.24
£12.24 - £12.24
Current price £12.24
In stock

4.2M x 75 x 33mm Redwood Decking Handrail Treated

Original price £12.24 - Original price £12.24
Original price
£12.24
£12.24 - £12.24
Current price £12.24

Redwood Decking Fillet Treated 4.2m x 45 x 12mm

Alter Supplies
Original price £3.60 - Original price £3.60
Original price
£3.60
£3.60 - £3.60
Current price £3.60
In stock

Redwood Decking Fillet Treated 4.2 x 45 x 12mm

Original price £3.60 - Original price £3.60
Original price
£3.60
£3.60 - £3.60
Current price £3.60