Timber decking in Perth's northern suburbs
Northern Decking Co builds hardwood timber decks in merbau, jarrah and spotted gum across the City of Joondalup and the City of Wanneroo. Timber gives a warmer deck underfoot and a finish that can be brought back with oil. The contractor quotes free after seeing the site.
What you get
Three hardwoods, chosen for the site
Merbau is the most common decking hardwood in Perth. It is a rich red-brown that deepens with oil, dense, stable and durable above ground. It bleeds a dark tannin in its first few months, which stains light paving and render below the deck until it washes out, so the contractor plans for that on new alfresco areas.
Spotted gum is an Australian hardwood with more variation in colour from board to board, from pale to mid brown, and a wavy grain. It bleeds less than merbau, holds colour well and is one of the timbers listed as bushfire-resisting in AS 3959, which matters on lots inside the DFES bushfire prone map.
Jarrah is the West Australian timber. Deep red when new, it silvers to grey quickly if it is left unoiled. It is heavy, hard and durable, and for many owners it is the deck that looks right against a Perth home.
The frame under the boards
Hardwood boards go on a frame of treated pine or hardwood bearers and joists, on stumps into the sand or on stirrups off concrete footings, at 450 mm centres for standard boards. Near the coast the fixings are stainless steel. Everywhere else hot-dipped galvanised is the minimum. The contractor pre-drills the boards, because hardwood splits if you drive a screw straight into it near an end.
Screws or hidden fixings
Timber decks are usually face-screwed, two stainless screws per joist crossing, set in straight lines that become part of the look. Grooved hardwood boards can take hidden clips like composite does. Face screwing is the stronger and more repairable choice; hidden fixing is the cleaner one.
Oil, and how often
Hardwood decking is oiled after the first few weeks of weather have taken the surface tannins off, then re-oiled when the colour goes flat and water stops beading. A deck in full sun needs it sooner than a shaded one. There is no fixed calendar and anyone who gives you one has not seen your deck. Left unoiled, all three timbers go grey. Some owners like that; it does not harm the board if the fixings are right.
Ground and approvals
Most of the corridor is coastal sand, which takes a standard stump footing. Parts of the far north have limestone close to the surface, and footings there are core drilled. The council side is different in Joondalup and Wanneroo, and the panel below has the current rules for each.
How it goes in
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Joists
Joists go across the bearers at the centres the board maker specifies, typically 450 mm for hardwood and tighter for composite.
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Boards
Boards are laid from the house out with an even gap, fixed with screws or hidden clips.
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Finish
Fascia and trims go on and the deck is oiled, or a composite deck settles into its finished colour.
What changes the price
- Size
- More area is more boards, joists and fixings, but the rate per square metre usually falls as the deck gets bigger.
- Height
- A deck over 500 mm needs more structure, probably a balustrade, and may need planning approval and privacy screens.
- Material
- Composite costs more per board than most hardwood, and hidden clip systems add to that, but it is the last money you spend on the surface.
- Access
- A deck at the back of a narrow lot means carrying everything through by hand and takes longer.
- Approvals and engineering
- A building permit, drawings and any engineering for a raised deck are real costs that sit outside the build itself.
We do not publish prices, because two decks of the same size can be very different jobs. Read what affects the cost of a deck, then get a free quote from the contractor.
Approvals
City of Joondalup
- Building permit requirements depend on the deck. Confirm with the City of Joondalup on 9400 4000 before work starts.
- For a single house or grouped dwelling, development (planning) approval is not required for decking 500 mm or less above natural ground level.
- Decking over 500 mm can avoid planning approval if it meets the R-Code setbacks for the lot's density.
- A deck within 7.5 m of a side or rear boundary needs a privacy screen at least 1.6 m high.
City of Wanneroo
- All decking requires a building permit, regardless of height or floor area.
- Planning approval may be required for decking over 500 mm above natural ground level.
- Decking over 500 mm is treated like a balcony, with a 7.5 m setback to side and rear boundaries unless a reduced setback is approved.
Check the DFES Map of Bush Fire Prone Areas for your lot. Decks in a bushfire prone area have to meet the BAL construction requirements of AS 3959. DFES Map of Bush Fire Prone Areas.
Questions people ask
Which hardwood is best for a deck near the beach?
Spotted gum and merbau both handle salt air well when they are oiled and fixed with stainless screws. Merbau bleeds tannin onto light paving for its first few months, which is worth knowing on a new alfresco.
How often does a timber deck need oiling?
It depends on sun and exposure rather than a fixed calendar. A deck in full sun needs a coat sooner than a shaded one. The sign is the colour going flat and water no longer beading.
Can timber decks be built in bushfire prone areas?
Yes, with the right species and detailing for the lot's BAL rating under AS 3959. Check the DFES map for your lot and tell us the rating when you enquire.
Get a free quote
Send your details. The contractor calls you, looks at the site and quotes in writing. No obligation.