This is usually the first real fork in the road when planning a deck, and it's an easy one to get anxious about — the price difference is real money, and nobody wants to spend it on the wrong material and regret it in five years. There's no universally "right" answer here, but there is an honest one for your specific situation. Here's the comparison without the sales pitch.
Cost Difference: What You're Really Paying For
As a general planning range, treated pine runs $35-$55/m² for board supply and $160-$220/m² fully installed on a standard subframe. Hardwood like Merbau sits at roughly $75-$115/m² supply only, or $180-$280/m² installed — treated pine costs roughly half what hardwood does, which typically works out to $4,000-$6,000 in your pocket for a standard-sized deck. That gap isn't a mystery: you're paying for a naturally dense, decay-resistant timber species with hardwood, versus a fast-growing softwood that gets its durability from chemical treatment rather than the timber itself.
Lifespan in a Coastal Environment
Properly maintained treated pine lasts 15-25 years on the Central Coast — we've got treated pine decks around Terrigal pushing 20 years and still solid. Hardwood lasts longer again, typically 25-40 years with oiling every 2-3 years. Both figures assume you're keeping up with basic maintenance; a neglected deck of either material will fall well short of these numbers, and coastal salt air and humidity are part of why maintenance matters more here than inland.
Maintenance: What Each Timber Actually Needs
Treated pine needs more frequent attention — annual cleaning and oiling keeps it performing and looking right, and you'll want to wait at least six months, ideally a full year, before the first stain or oil so the timber isn't still saturated with treatment chemicals and moisture. Hardwood is comparatively lower-maintenance, needing an oil treatment roughly every 2-3 years rather than annually, though the first coat typically goes on sooner after installation to protect the timber while it settles in. Neither is "no maintenance" — that's really only true of composite decking — but hardwood asks less of your time over the years in exchange for its higher upfront cost.
Look and Feel — Does Treated Pine Look "Cheap"?
This is the concern we hear most often, and it's worth answering honestly: fresh, unfinished treated pine does look plainer than hardwood, and if it's left untreated or poorly finished, it can look exactly like what people picture when they say "cheap decking." That's a finishing problem, not an inherent one. Stained or oiled well, treated pine develops real rustic character as it weathers, and a good finish goes a long way toward making it look intentional rather than budget. Hardwood's advantage here is that it looks premium immediately, with no finishing effort required to get there — treated pine can look genuinely good, it just takes a bit more work and a bit more time to arrive at that point.
Which One Suits Your Property and Budget
If this is a first home, an investment property, or a budget-conscious build, treated pine delivers real value — good performance for a lower upfront cost, with maintenance that's manageable if you keep on top of it. If you're in your long-term home and want a premium look from day one with less ongoing maintenance to think about, hardwood is worth the extra spend. There's also a third option worth a mention if neither maintenance schedule appeals: composite decking costs more again than hardwood but needs essentially none of the oiling either timber requires. Whichever direction you're leaning, getting a custom deck design and build quoted for your actual site is how you turn "which material" into a real number for your project.
Our Honest Recommendation Based on What We've Built
We install a genuine mix of both, and neither one gets pushed over the other by default — the right answer depends on what you told us above about your timeframe, budget and how much upkeep you're realistically going to do. If pressed for a rule of thumb: treated pine is the smart, practical choice when budget matters and you don't mind an annual maintenance job; hardwood is the choice when you want the premium result now and you're planning to be in the house long enough for the lower long-term maintenance to pay off.
Still not sure which is right for your project? Get in touch for a free on-site quote and an honest recommendation either way.