Decking in Alkimos
Northern Decking Co builds composite and BAL-rated decks in Alkimos, the planned coastal city in the City of Wanneroo. Most jobs are a first deck on a new lot, taking the alfresco onto the lawn, with BAL construction to AS 3959 where the DFES map applies. Every deck needs a Wanneroo building permit, and the contractor quotes free on site.
- Postcode
- 6038
- Council
- City of Wanneroo
- Coastal lot rules
- Apply
- Last reviewed
- October 2026
Decks that suit Alkimos homes
Alkimos takes its name from a ship that ran aground off the coast in 1963, and for decades after that the land stayed what it had always been: scrubland, woodland and heath of the Swan Coastal Plain. The planned satellite city changed that. By 2025 housing estates had taken up much of the northern and southern parts of the suburb, on the way to a population that LandCorp put at 55,000 once the area is complete. A deck in Alkimos is almost always the first deck on a new lot, built for a household that is still settling in, and designed around three things: the permit, the ground, and the DFES map.
A first deck, with the permit built in
Alkimos homes are mostly less than fifteen years old, with an alfresco under the main roof and a lawn behind it waiting to be used. The usual job is a low deck level with the alfresco slab that carries the outdoor area past the roofline. In the City of Wanneroo all decking requires a building permit, regardless of height or floor area, so the permit is the first step on every Alkimos job rather than a surprise at the end. Ask for the quote to say who prepares the drawings and who lodges.
Composite for households still settling in
Few owners in a new estate want to spend weekends oiling timber, so composite decking is the common choice here: hidden stainless clips, no splinters, and colours that hold under the afternoon sun off the ocean. Lighter greys and sand tones stay cooler underfoot on a west-facing yard. Hardwood in merbau or spotted gum remains the pick for owners who want timber and will oil it.
Two kinds of dune
The district structure plan that covers Alkimos describes two dune systems: Quindalup dunes of calcareous sand nearer the coast, and Spearwood dunes further east where the sand often sits over limestone within 2 m of the surface. That is a district record, not your backyard, and on most lots the footings go into sand. If the first hole finds rock, the contractor core drills that footing and tells you before the quote is final.
Where the estate is still growing
Parts of Alkimos are still being built out, and some lots sit near land that is yet to be developed. We do not say whether any suburb is or is not bushfire prone; check your address on the DFES Map of Bush Fire Prone Areas. If your lot is inside a mapped area, the deck is designed to the BAL level of your assessment under AS 3959, with bushfire-resisting timbers at the lower levels, non-combustible materials as the level rises, and the gaps and the space under the deck detailed to match. The permit application carries the BAL assessment.
What to know before you build in Alkimos
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.
Salt air
Alkimos is a coastal suburb, so the fixings, hangers and stirrups are stainless steel and the frame is detailed to dry out. Composite boards suit lots within reach of the sea breeze; hardwood works too when it is oiled and fixed properly.
The ground
The district structure plan for Alkimos and Eglinton records two dune systems: Quindalup dunes of calcareous sand toward the coast and Spearwood dunes further east where limestone usually occurs within 2 m of the surface and is sometimes exposed. That is a district record, not a house lot, so the contractor expects sand and checks the first footing hole for rock.
Bushfire map
Check your lot on the DFES Map of Bush Fire Prone Areas. If it is inside a mapped area the deck is built to the BAL requirements of AS 3959. We do not say here whether Alkimos is or is not bushfire prone, because the map runs through suburbs and is revised.
How it goes in
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Footings
Stumps go into footings in the sand. Some sites in the far north hit limestone close to the surface and need core drilling.
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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.
Questions from Alkimos
Is Alkimos bushfire prone?
We do not say on this site whether a suburb is or is not bushfire prone, because the DFES Map of Bush Fire Prone Areas runs through suburbs and is revised. Check your own address on the map. If your lot is inside a mapped area, the deck is built to the BAL construction requirements of AS 3959 and the permit application includes the BAL assessment.
Do I need a permit for a deck on my new Alkimos home?
Yes. In the 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. Ask for the quote to say who prepares the drawings and who lodges the application.
Will my footings hit limestone in Alkimos?
It depends where in the suburb you are, and the only sure test is the first hole. The district structure plan records calcareous sand dunes nearer the coast and Spearwood dunes further east where limestone usually sits within 2 m of the surface. That is a district record rather than a statement about your yard. If rock turns up, the contractor core drills that footing and tells you before the quote is final.
What deck suits a new Alkimos estate home?
Usually a low composite deck level with the alfresco slab, carrying the outdoor area past the roofline. Composite needs no oiling and no splinters for bare feet, and lighter colours stay cooler on a west-facing yard. Hardwood in merbau or spotted gum is the alternative for owners who want timber and will oil it.
Nearby areas we cover
Read about composite decking and bal-rated decking, or our guide to deck approvals in joondalup and wanneroo. All areas.
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