If you've had a few different quotes come back looking surprisingly different for what feels like the same deck, the gap usually isn't the builder — it's the decisions baked into each proposal, some of which you may not have been asked about upfront. Timber decking has more genuine decision points than most home improvement jobs. Here are the five that matter most.
1. Timber species
This is usually the decision with the biggest impact on how the finished deck looks and how it ages. Treated pine is the practical, low-maintenance option and holds up perfectly well for a straightforward backyard deck, though it won't have the depth of colour or natural longevity of a hardwood. Merbau is the most common mid-to-upper choice in Sydney — good natural durability, a warm colour, and it's readily available. Spotted gum and blackbutt sit above that again, prized for their look and strength, but they take more care to work with.
The right choice usually comes down to how much ongoing maintenance you're happy to do, and how much the timber's appearance matters to the overall look of the space.
2. What's underneath the boards
The substructure — bearers, joists, footings — is invisible once the deck is finished, but it's what determines how the deck performs over time. A deck built on a slope, over uneven ground, or requiring engineered footings because of soil conditions needs a genuinely different approach to one built on flat, stable ground at an easy height. If a plan or quote doesn't specify what's been allowed for in the substructure, it's worth asking directly — this is the part that's easiest to underspecify and hardest to fix after the fact.
3. Size and shape
Worth saying plainly: complexity doesn't scale in a straight line with square metres. A simple rectangular deck is the most straightforward shape to build well. Add curves, multiple levels, built-in seating, or a wraparound shape, and you're adding genuine construction complexity and time on site — not just extra materials. If you're drawn to a more elaborate design, it's worth deciding early whether that complexity is worth trading off against a simpler, faster build.
4. Site access
A deck built where materials can be brought straight to the work area is a different job to one where every board has to be carried down a side path or through the house. Tight access is one of the most under-discussed factors in decking projects, and flagging it honestly at the planning stage — rather than letting it surface mid-build — avoids the kind of "surprise" that derails a timeline.
5. Council approval
Not every deck needs council approval, but height, size, and proximity to boundaries can trigger it. In NSW, decks over a certain height off the ground, or those attached to the dwelling above a certain size, often need a Complying Development Certificate or a full DA. This is a timing decision as much as anything — building in approval time from the start avoids it becoming the thing that stalls the whole project.
What good planning actually looks like
The homeowners who end up happiest with their deck are usually the ones who made these five decisions deliberately, upfront, rather than discovering them partway through. None of them are complicated on their own — the timber, the substructure, the shape, the access, and the approval process — but skipping past any one of them is where most of the friction in a decking project actually comes from.
Frequently asked questions
Is treated pine actually worth using?
For a lot of backyards, yes. It's stable, practical, and takes stain or paint well. The main trade-off is appearance and lifespan compared with hardwood — treated pine typically needs re-coating more often to stay protected.
How long does a standard deck build take?
A straightforward deck with good access is often 3–6 working days from footings to finished boards. Add time for council approval if it's needed, and more again for staining and curing before it's fully weather-ready.
Do I need a permit for a small deck?
Often not, if it's low to the ground and detached from the house — but this varies by council and by exactly how the deck is attached and how high it sits. It's worth a five-minute check before committing to a design.