What is the correct joist spacing for composite decking in New Brunswick?

Composite decking requires 12" on-center joist spacing in New Brunswick, which is closer than the standard 16" spacing used for pressure-treated lumber. This tighter spacing is critical because composite boards are more flexible than wood and need additional support to prevent sagging and bounce.

Most composite manufacturers — including Trex, TimberTech, and Fiberon — specifically require 12" joist spacing in their installation guidelines. Using 16" spacing with composite will void your warranty and create a bouncy, unsafe deck surface. The additional joists increase material costs by about 25-30%, but this is essential for proper performance.

New Brunswick's climate makes proper joist spacing even more important. Our heavy snow loads (250-300cm annually) put extra stress on deck surfaces throughout winter. Composite decking that's properly supported at 12" centers will handle this load without issue, while inadequately supported composite can sag permanently under snow weight.

For diagonal composite installation (popular for visual appeal), you'll need even closer spacing — typically 10" on-center. The diagonal orientation reduces the effective span strength of the boards, requiring additional support. Some premium composite lines like Trex Transcend can span 16" when installed perpendicular to joists, but check your specific product's span tables.

Joist sizing remains the same whether you're using wood or composite decking. For typical residential loads in New Brunswick, 2x8 joists work for spans up to 10 feet, while 2x10 joists handle spans up to 13 feet. The difference is purely in the spacing between joists, not their size.

When planning your composite deck project, factor this 12" spacing requirement into your budget from the start. Many homeowners are surprised by the additional framing costs, but proper support is what makes composite decking perform beautifully for decades without the annual maintenance that wood requires in our Maritime climate.

Professional installation is recommended for composite decking projects, especially when dealing with the precise spacing requirements and proper fastening techniques. Composite boards expand and contract differently than wood, requiring specific gap spacing and fastener placement that experienced deck builders understand.

Need help finding a deck builder experienced with composite installation? New Brunswick Decks can match you with local contractors who understand these spacing requirements and NB's building conditions.