Decking is sold by the lineal metre, so the main decisions are the species, the board size and how many metres the deck needs. This guide covers the ranges JBM lists and how to work out an order.
Species
JBM lists Australian hardwood decking in species such as Spotted Gum, Blackbutt, Ironbark and Merbau, and treated pine decking for budget decks. In general terms:
- Spotted Gum: a dense, durable hardwood with a wavy grain and colour from pale brown to chocolate. Popular for decks that will be oiled and left to show the timber.
- Blackbutt: a pale, straight-grained hardwood that takes oil and stain evenly. One of the species suited to higher bushfire attack levels; check the requirement for your site.
- Ironbark: among the hardest and most durable Australian species, deep red to brown. Heavier to work and worth pre-drilling.
- Merbau: a stable, durable imported hardwood with a rich red-brown colour. It bleeds tannin when new, so keep it off pale paving until it has weathered.
- Treated pine: softwood treated to H3 for outdoor use above ground. The lowest cost option; paint or stain it for the best life.
JBM to confirm: which species it recommends for coastal, pool and high traffic decks.
Sizes and grades
Decking boards are described by width and thickness in millimetres, for example 86 x 19 or 136 x 19. Narrower boards suit smaller decks and move less; wider boards cover ground faster. Thicker boards (above 19 mm) span further between joists.
Hardwood decking is usually offered as Select grade (fewer features, a cleaner look) or Standard and Better (sound boards with more natural character such as gum vein and colour variation). Both are structurally sound; the choice is appearance and price.
Random lengths
Most decking is supplied in random lengths: you order the total metres and the pack is made up of boards of varying lengths, typically between 0.9 m and 5.4 m. Individual lengths are not selected, so plan joins over joists. Where a product is sold as set stock lengths instead, the product page lets you choose the length and the number of pieces.
How many metres do I need?
- Measure the deck area in square metres (length x width).
- Divide by the board coverage: board width plus the gap, in metres. For 86 mm boards with a 4 mm gap that is 0.09 m, so 1 m² needs about 11.1 lineal metres.
- Add an allowance for cuts and waste. Five to ten percent is common for a simple rectangle; more for angles and steps.
Enter the total metres on the product page and the price is calculated for you, GST included. Delivery is calculated at checkout, or you can collect from the JBM warehouse.
Fixings and finishing
Use stainless steel or hot dip galvanised fixings outdoors, pre-drill hardwood near board ends, and oil or seal the deck once it has weathered as the finish manufacturer directs. JBM to confirm: the fixings and finishes it stocks.