Decking Calculator
Planning a new garden deck? Our calculator helps you accurately estimate all the materials you'll need, from boards and joists to screws and weed membrane. Get a clear cost breakdown and start your DIY project with confidence.
Deck Dimensions & Options
Standard UK decking boards are 140mm or 145mm wide.
Standard spacing is 400mm. Reduce to 300mm for stronger support.
Material Costs
Your Results
This is an estimate and does not include wastage, fixings for the frame, or delivery charges. Always buy 10-15% extra material to account for cuts and mistakes.
Understanding Your Decking Project
Choosing Your Materials
The type of decking board you choose impacts both the look and longevity of your deck. Softwood is cost-effective, while hardwood and composites offer greater durability. Remember to use pressure-treated timber for your joist frame to prevent rot.
Building a Solid Frame
The subframe is the most critical part of your deck. Ensure it is level, square, and well-supported. The standard 400mm joist spacing is suitable for most applications, providing a strong and stable base for your decking boards. A well-built frame is key to a long-lasting deck.
Fixings and Finishings
Using proper decking screws is essential; they are coated to resist corrosion. Pre-drilling pilot holes near board ends can prevent splitting. Consider adding a border frame for a professional finish, as calculated by our tool. For another garden structure, see our Fencing Calculator.
Frequently Asked Questions
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