Deck building guides
Plain answers to the questions that come up when you plan a deck: how far joists can span, how big the footings should be, how many boards to buy, and the rules for stairs and railings in Australia and the US.
Deck joist spacing and span tables (AU and US)
Joist spacing is set by the decking: usually 450 mm in Australia and 16 in. in the US. Span tables then tell you which joist size reaches between your bearers.
Deck footing size, post spacing and bearer spans
Post spacing comes from how far your bearer or beam can span, and footing size from how much deck each post carries and your soil. Typical NCC and IRC figures.
How many deck boards do I need? A simple calculator
Count rows from the board width plus gap, then match your run to the stock lengths on sale. The fit between the two decides how much ends up as offcut.
Breaker boards, butt joints and picture frame decking
A breaker board replaces butt joints on a long deck. Placed to suit your board lengths it can cut offcut to almost nothing; placed badly it wastes a lot.
Deck stair rise and run: how many steps do you need?
How to count the steps for your deck and size each riser and going under the NCC and the IRC, with worked examples and when a handrail is needed.
Deck railing height and balustrade rules (AU and US)
When a deck needs a balustrade or guard, how high it must be and how far apart balusters can go under the NCC and the IRC, with a worked baluster count.
Composite vs timber decking: cost, heat and upkeep
A fair comparison of composite and timber decking in Australia and the US: board prices, heat underfoot, upkeep, warranties and hidden fixings versus face screws.
Rather see it for your own deck?
Draw your deck and Deckulator works these rules out for you, with a materials list and cut list.
Start designing