Home & DIY
How many deck boards do you need?
How many decking boards and screws for your terrace from its size, plank length and gap.
Quick answer
Decking math is row count × boards per row, not guesswork from m² alone — because the gap between planks is part of the coverage and every end joint wants a full-length board or a planned half. Run boards parallel to the long side when you can: fewer cuts, cleaner lines, less waste.
Deck boards to buy
44 boards
- Deck screws (approx.)
- 330
- Floor area
- 15 m²
Assumes boards run along the length. Gap lets rainwater drain — 5 mm is standard for softwood. Plan 20–25 stainless screws per m². Treat or buy pre-treated wood for ground contact.
How it works
The calculator counts rows from terrace width, board width and gap, then boards per row from length ÷ plank size, with your waste percentage on top. Stainless screws — about 22 per m² — beat nails for outdoor life. Leave 5 mm between boards for drainage; tight decks rot from trapped water. Compare stainless deck screws and oil before you cut the first plank.
Frequently asked questions
How much waste should I add for a wood deck?+
10% covers a simple rectangle with one or two cuts per board. Irregular shapes, diagonal borders or lots of posts push you to 12–15%. Buying one extra board is cheaper than a second trip to the yard.
Softwood or composite (WPC) decking?+
Softwood (pine, larch) is cheaper but needs annual oil or stain. Hardwood and WPC cost more upfront and need less maintenance — WPC has uniform dimensions, which simplifies the row math. Both use similar spacing and screw counts.
Which way should deck boards run?+
Along the long dimension of the terrace when possible — fewer butt joints. Joists run perpendicular to the boards, typically every 40–50 cm for 28 mm boards. Always check local building codes for balcony loads.
Do I need gaps at the house wall?+
Yes — leave 8–10 mm against walls and other fixed points so the wood can expand with humidity. Use a hidden starter clip or a cover strip so the gap does not show.
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