Frame material is one of the earliest decisions in a build, and one of the hardest to reverse. It affects your budget, your program, your termite and bushfire exposure, and even how much footing work your site needs.
The honest answer is that neither material is universally better. Timber generally wins on upfront cost and thermal simplicity. Light gauge steel wins on termites, fire, dimensional stability and weight. What matters is which of those advantages actually apply to your project.
Here's a straight comparison from an engineering perspective.
Light gauge steel (LGS) framing uses cold-formed steel — thin galvanised or zinc-coated coil roll-formed into C-section studs, tracks and noggings that directly replace their timber equivalents.
Base metal thickness typically ranges from around 0.55 mm for non-load-bearing partitions up to 1.15 mm and above for load-bearing walls. Products such as BlueScope's TRUECORE are common in the Australian residential market, and self-drilling (Tek) screws are the standard fastener.
It is not the same thing as structural steel — no hot-rolled beams and columns. It's a framing system, engineered to a different standard.
| Light gauge steel | Timber | |
|---|---|---|
| Primary standard | AS/NZS 4600 (Cold-formed steel structures) + the NASH Standard for Residential and Low-Rise Steel Framing | AS 1684 series (Residential timber-framed construction) |
| Bushfire | NASH Bushfire Standard (referenced by the NCC at certain BAL levels) | AS 3959 |
| Also applies to both | NCC, AS 2870 (slabs and footings), AS/NZS 1170 (structural design actions) | |
Whichever you choose, your engineer's documentation should reference the applicable pathway.
| Light gauge steel | Timber | |
|---|---|---|
| Upfront cost | Higher | Lower |
| Termites | Immune | Requires management |
| Fire / bushfire | Non-combustible | Needs detailing |
| Dimensional stability | Excellent — no shrinking, warping or twisting | Can move, shrink and warp |
| Weight | Lighter | Heavier |
| Spans / open plan | Higher strength-to-weight, wider spans | More limited without engineered members |
| Thermal performance | Conducts heat — needs thermal breaks | Naturally lower bridging |
| On-site modification | Harder — factory prefabricated | Easy |
| Waste | Low — cut to length off site | Higher |
| Coastal corrosion | Needs correct coating specification | Not applicable |
| Embodied energy | Higher | Lower |
| Trade familiarity | Narrower pool | Universal |
Termite-prone areas. Steel is impervious to termites and borers, which simplifies compliance with the NCC's termite requirements. One nuance worth knowing: even with a steel frame, slab edge protection is still required — termites can still reach susceptible elements like skirtings, architraves and plasterboard.
Bushfire-prone land. Non-combustible framing is a meaningful advantage, with a defined compliance pathway through the NASH Bushfire Standard at certain BAL ratings.
Reactive soil sites and second-storey additions. This is the one most people miss. A lighter frame means less dead load reaching your footings — which on a reactive clay site, or when adding a level to an existing home, can reduce the footing work required. Sometimes it's the difference between a project needing underpinning and not. (See our guide to [second-storey additions].)
Long spans and open-plan layouts. A higher strength-to-weight ratio allows wider spans without heavy engineered members.
Precision and program. Frames are manufactured to tight tolerances off site, arrive straight and true, erect quickly and generate very little waste. Straight walls also make life easier for every trade that follows.
Volume builders. Consistency across lots reduces variation in installation time and defect rectification.
Lower upfront cost. On a low-risk site with no termite or bushfire driver, timber is usually the cheaper start — though the gap has narrowed with timber supply pressures and rising interest in termite- and fire-resistant construction.
Thermal performance. Timber is a poorer conductor of heat, so it bridges far less. That makes energy compliance simpler.
On-site flexibility. Changes during construction are far easier in timber. If your project is likely to evolve on site, that matters.
Trade familiarity. Almost every carpenter works in timber. The pool of experienced steel framing installers is smaller in some regions.
Lower embodied energy. Timber generally performs better on this measure.
Steel conducts heat readily, so an LGS frame can create thermal bridges through the building envelope. Left unaddressed, that undermines energy efficiency and can contribute to condensation problems.
It's entirely solvable — thermal breaks, cavity battens and continuous insulation are standard solutions, and well-detailed steel-framed homes meet high performance targets. But it has to be designed in, not assumed. Ask how thermal breaks and your condensation strategy integrate with the cladding system before you commit.
Steel framing near the coast needs the appropriate coating specification for its exposure. Galvanised and zinc/aluminium-coated products are used precisely for this reason, but the specification should match the environment rather than be assumed.
Indicative Australian supply-only figures for light gauge steel framing:
| Indicative range | |
|---|---|
| Single-storey home (frame supply only) | $15,000 – $35,000 |
| Double-storey home (frame supply only) | $30,000 – $60,000 |
| Steel wall framing | Roughly $100 – $150 per m² of wall area |
| Load-bearing steel studs (supply) | Roughly $18 – $35 per lineal metre of wall |
These exclude installation labour, crane hire, concrete and finishing trades. Timber is generally lower upfront, but compare lifecycle cost too — no termite treatment, minimal movement and fewer defect callbacks shift the equation over time.
Regardless of material, load-bearing framing requires structural engineering and certification. Your building permit documentation will include structural drawings and specifications referencing the relevant standard.
Light gauge steel carries one additional requirement: shop drawings. Because frames are manufactured off site, the fabricator needs panel layouts, member schedules, connection details and set-out — documentation that translates the engineering design into something a roll-forming line can build accurately. Poor shop drawings are one of the most common causes of delays and rework on steel-framed jobs.
A quick way to narrow it down:
The most useful thing you can do is get both priced for your plans, on your site, rather than relying on general rules.
QED Engineers provides light gauge steel design to AS/NZS 4600 and the NASH Standard, plus LGS shop drawings and detailing — wall panels, floor cassettes and truss sheets ready for fabrication — for projects across [QLD, NSW, VIC & ACT].
Send us your plans for a fast fee proposal.
Request a Free Quote | Call: 0421 157 963
This article is general information only. Frame selection and design must suit your specific site, climate, BAL rating and structural requirements, and be documented by a qualified structural engineer.
Is steel framing better than timber? Neither is universally better. Steel is superior for termite resistance, fire, dimensional stability and weight; timber is typically cheaper upfront, easier to modify on site and better on thermal bridging. The right choice depends on your site and priorities.
Is light gauge steel framing more expensive? Generally yes upfront, though the gap has narrowed. Supply-only steel framing for a single-storey home commonly runs $15,000–$35,000. Lifecycle costs can be lower given no termite treatment and minimal movement.
Do steel-framed homes still need termite protection? The frame itself is immune, but slab edge protection is still required. Termites can attack other susceptible elements such as skirtings, architraves and plasterboard.
Is steel framing good for bushfire areas? It's non-combustible, which is a real advantage, and the NASH Bushfire Standard provides a compliance pathway referenced by the NCC at certain BAL levels. Detailing still matters — the whole envelope has to perform, not just the frame.
Does steel framing make a house hotter? Not if it's detailed properly. Steel does conduct heat, so thermal breaks and continuous insulation are needed. With those, steel-framed homes achieve high energy performance.
Do I need shop drawings for a steel frame? Yes. Because frames are prefabricated off site, fabricators need detailed shop drawings — panel layouts, member schedules and connection details — derived from the engineering design.
