Garden Decking Calculator

Calculate the materials for a practical garden decking build using standard joist and post spacing.

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 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 - Garden Decking Calculator

  • 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

Garden decking notes

This is the garden-decking variant of the main decking estimator, useful for landscaping-led searches while keeping the same practical build assumptions.

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.