How much extra decking should I order?
Count real board lengths, not square metres. Then add a small allowance for cuts.
Area alone under-counts. Boards come in fixed lengths, and the offcut from one row is often too short for the next. So the honest count is rows of the deck packed into the lengths your merchant stocks.
On top of that, a straight board layout wants around 5 to 10 percent for bad boards and mis-cuts. Diagonal or herringbone layouts waste a lot more, because every end is cut at an angle.
If the two numbers disagree, buy the bigger one. A second trip to the yard for three boards costs you more than the boards.
Check before you buy or dig
- Check which lengths your yard actually has in stock before you finalise the deck width.
- Composite boards and their hidden fixings are usually not returnable once cut, so measure twice.
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Count boards for your deckA general answer, not a structural design. Local rules, ground and loads decide the final build.