Hardwood vs Treated Pine Fencing in Sydney

If you are pricing a timber fence in Sydney, you will hear both words in the same conversation: hardwood and treated pine. They are not simply a cheap option and an expensive one. They fail in different ways, they are used in different parts of the same fence, and the right answer usually depends on which part you are talking about.

The short answer

For most suburban Sydney fences, the sensible build is hardwood posts and rails with either hardwood or treated pine palings, or a full treated pine fence where the timber is properly rated for its job. Treated pine is only a problem when the wrong treatment level is put in the ground. Hardwood is only a problem when someone assumes every board of it is durable heartwood.

What matters far more than the label is the part of the fence, the treatment rating, and how the posts are set. Get those three right and either material gives you a long-lived fence.

What "treated pine" actually means

Treated pine is plantation softwood that has had preservative forced into it under pressure. Untreated, it would not last long in a Sydney backyard. Treated, it becomes a genuinely durable fencing timber.

The number that matters is the hazard level stamped or tagged on the timber. In broad terms, H3 is rated for outdoor use above ground, and H4 is rated for in-ground contact. A fence post lives in the ground, so it needs the in-ground rating. Rails and palings sit above it.

• H3 treated pine: rails, palings, capping, anything above ground and exposed to weather.

• H4 treated pine: posts and anything buried or sitting in damp soil.

• The common failure: H3 posts put in the ground because they were on the truck. They will rot at ground level years before the rest of the fence is tired.

Ask your supplier or your fencer which rating is going into each part of the fence, and check the tags on delivery. It is a thirty-second question that decides how long the fence lasts. Treatment types and ratings vary between suppliers, so go by the product's own documentation rather than an assumption.

What "hardwood" actually means

Hardwood in Australian fencing usually means a dense native eucalypt. Species used around Sydney include ironbark, spotted gum and blackbutt, with merbau and similar timbers turning up in gates and screens where a cleaner finish is wanted.

Hardwoods are graded by natural durability class, and the durability sits in the heartwood, not the pale sapwood at the outside of the board. A hardwood post with a lot of sapwood on one face is not carrying the durability rating you think you bought. Good merchants sell posts with the sapwood removed or the grade stated. It is worth asking.

The advantage of a durable hardwood is that its resistance is structural rather than applied. There is no treatment envelope to breach, so a cut, a notch or a drilled hole does not create a weak point the way it can in treated softwood.

Where each one genuinely wins

Posts

This is where the decision matters most, because posts are what fail first in almost every timber fence. Either durable hardwood or correctly rated H4 treated pine will do the job. What will not do the job is H3 pine, a hardwood post with heavy sapwood, or any post set into a hole that holds water. More on why posts go first in our guide to how long a timber fence lasts in Sydney.

Rails

Rails take bending load and carry the palings. Hardwood rails are stiffer and hold nails and screws hard. Treated pine rails are lighter, easier to work and less likely to split at the ends. Both are common and both are fine at the right size and spacing.

Palings

Palings are cladding. They take weather but almost no load. Treated pine palings are straighter and more consistent out of the pack. Hardwood palings are heavier, more varied in colour and tend to look better as they weather. This is largely an appearance and budget decision rather than a durability one. Our timber paling fence guide covers paling layout, lapping and capping in more detail.

Gates

Gates are the one place we lean hardwood almost every time, at least for the frame. A gate is a moving, self-supporting structure that is opened thousands of times, and the stiffer, denser timber holds its hardware and its shape better. Anything that sags is expensive to fix later.

Appearance, and how each one ages

New treated pine has a green or brown cast from the preservative and a uniform grain. Left alone it silvers off to grey over a few seasons, fairly evenly. Painted or solid-stained, it takes coatings well and is the easier of the two to keep a consistent colour on.

Hardwood starts with far more colour variation, from deep red-brown to honey, and weathers to a silver-grey with more character and more movement between boards. It suits an oil finish better than a film-forming paint, because the natural oils in some species fight paint adhesion.

Neither weathers badly. They just weather differently, and there is no finish that stops the process outdoors. See our fence maintenance tips for what actually extends the life of a coating.

Movement, cupping and warping

Timber moves. Sydney's swing between humid summers and dry winters works every board in a fence.

• Treated pine: more likely to cup and twist if it goes up green or wet, less likely to split at fixings. It also takes a while to dry out after treatment.

• Hardwood: holds its shape better once seasoned, but is more likely to split at nail holes and at board ends if it is fixed dry and hard with no pre-drilling.

Both problems are largely installation problems. Correct gaps, fixings placed away from board ends, and pre-drilling in dense hardwood solve most of it.

Cost, without the guesswork

As a rule, durable hardwood costs more per metre than treated pine, and the gap widens on posts and on long runs. But the material is only one part of a fence quote. Removal and disposal of the old fence, access, slope, ground conditions and the number of gates often move the number more than the choice of timber does.

We do not publish fixed prices, because a fence on a flat, open backyard and the same fence behind a narrow side gate on a sloping block are different jobs. What goes into a quote, and what to compare between quotes, is set out in our Sydney fencing cost guide.

Sydney conditions that should influence the choice

• Reactive clay soils: much of Sydney sits on clay that swells and shrinks. That movement works posts loose over time regardless of the timber, which is why footing depth and diameter matter more than species here.

• Coastal exposure: salt-laden air is harder on fixings than on timber. Near the coast, the galvanising grade of nails, screws, bolts and brackets is the thing to specify carefully.

• Termites: both correctly treated pine and durable hardwood heartwood resist termites, but no timber fence is a termite barrier. A fence in contact with soil, garden beds or mulch is still worth inspecting.

• Bushfire-prone land: if your property is mapped as bushfire prone, construction requirements can apply to structures on it. Check with your council and the NSW Rural Fire Service rather than assuming a standard fence build is acceptable.

• Damp, shaded southern boundaries: a run that never gets sun stays damp and grows more mould. This is where in-ground rating and drainage around posts earn their keep.

What most Sydney fences actually end up being

In practice the majority of timber fences we build and repair are mixed. Hardwood or H4 pine posts, hardwood or H3 pine rails, and palings chosen on appearance and budget. That is not a compromise. It is putting the more durable, more expensive timber where the load and the moisture are, and the lighter, cheaper timber where neither is.

If you are weighing timber against steel rather than one timber against another, our Colorbond versus timber comparison covers that decision, and the range of fence types we build is on our Sydney fencing page.

How to decide in five minutes

• Are the posts rated for in-ground use? If the answer is not clearly yes, stop there.

• Do you want to paint the fence a set colour? Treated pine is the easier surface.

• Do you want the fence to look like timber as it greys off? Hardwood ages with more character.

• Is there a gate, especially a wide one? Put hardwood in the frame.

• Is budget the binding constraint? A correctly rated treated pine fence is a genuinely good fence, not a downgrade.

If an existing fence is only partly gone, replacing posts or rails rather than the whole run is often the better move. That is covered in when to replace a fence, and we also do fence repairs across Sydney.

Frequently asked questions

Is treated pine as good as hardwood for a fence?

For the job it is rated for, yes. H4 treated pine in the ground and H3 above it will give you a long-lived fence. The problems people attribute to treated pine are almost always understated ratings or poor footings rather than the material itself.

Can I mix hardwood and treated pine in the same fence?

Yes, and most fences do. Hardwood posts with treated pine rails and palings is a very common and sensible build. The only thing to keep consistent is the fixings, which should suit the harder timber and the exposure.

Which one lasts longer?

Set up correctly, both last a long time and the difference is smaller than the price gap suggests. Durable hardwood heartwood generally has the edge in the ground, but a well-detailed H4 pine post beats a sapwood-heavy hardwood post every time. Footing quality and drainage separate long-lived fences from short-lived ones more than species does.

Do I have to oil or paint a new timber fence?

No. Left bare, both timbers weather to grey without losing structural integrity. Coating is about appearance and about slowing surface checking, not about keeping the fence standing. If you do coat it, let new timber dry out first and follow the coating manufacturer's guidance on timing.

Can I use hardwood palings on an existing pine frame?

Usually, but check the rails first. Hardwood palings are noticeably heavier and older or undersized pine rails may sag under the extra weight over a long run. If the frame is sound and correctly sized, it is not a problem.

Talk it through before you order timber

The timber decision is easier once someone has looked at your boundary, your soil, your slope and your access. We build and repair timber fencing across Sydney, from the Sutherland Shire and St George through to the Inner West and Eastern Suburbs, and we are happy to explain what we would use on your job and why. Get in touch for a quote.

Also worth reading: Painting a Picket Fence: A Sydney Guide