Decking Project Estimator

Calculate decking boards, joists, posts, screws and ground preparation materials for a complete deck build.

Decking materials for a 6m by 1.8m deck

For a deck measuring 6 metres by 1.8 metres, this estimate recommends 29 boards (3.6m lengths) plus joists at 400mm centres, 150mm noggins, posts, screws, weed membrane and sub-base using the default 2026 UK assumptions shown below.

  • Deck area10.80 m²
  • Deck boards29 boards (3.6m lengths)
  • Joists6 joists / 36.00 lm
  • Noggins15 pieces (150mm timber)
  • Posts10 posts
  • Structural bolts20 bolts
  • Decking screws172 screws
  • Weed membrane11.88 m²
  • Sub-base1.08 m³ / 1.94 tonnes

Results - Decking Project Estimator

  • Deck area10.80 m²
  • Deck boards29 boards (3.6m lengths)
  • Joists6 joists / 36.00 lm
  • Noggins15 pieces (150mm timber)
  • Posts10 posts
  • Structural bolts20 bolts
  • Decking screws172 screws
  • Weed membrane11.88 m²
  • Sub-base1.08 m³ / 1.94 tonnes

How this decking estimator works

This estimator builds a practical bill of materials for a ground-level deck using common 2026 UK assumptions: decking laid over joists at 400mm centres, 150mm noggins, two structural bolts per post, plus weed membrane and sub-base for ground preparation. Pick a board length of 2.4m, 3.6m or 4.8m and choose a wastage allowance of 5%, 10% or 15% depending on how simple or complex your layout is.

Disclaimer

Material quantities shown are estimates for guidance only. Although typical UK wastage and compaction allowances have been included, actual requirements may vary depending on site conditions, installation methods, and material differences. Please confirm quantities with your installer or supplier before ordering. We accept no liability for inaccuracies, financial loss, or delays arising from the use of these estimates.