By QED Consulting Engineers — structural & civil engineers, Notting Hill, Melbourne
Light gauge steel (LGS) and timber are the two main framing systems used in Australian homes. Timber is the traditional choice — easy to work with and lower in upfront material cost — while light gauge steel offers dimensional stability, termite resistance and non-combustibility. The right framing system for your build comes down to your site, your priorities and good engineering.
Here's how the two compare, and what to weigh up before you decide.
What is light gauge steel framing?
Light gauge steel framing uses thin, high-strength galvanised steel that is cold-formed (roll-formed at room temperature) into studs, tracks and C- or Z-sections. Australian residential framing commonly uses high-strength grades such as G550, and branded steel coil like TRUECORE, which allows thinner, lighter members without losing capacity.
Because the sections are cut to exact dimensions from a digital model — often via CNC machinery — LGS frames are highly precise, with less on-site cutting and waste. The system is designed and certified to Australian Standards for cold-formed steel structures.
What is timber framing?
Timber framing is the most common system in Australian housing. It uses softwood studs, plates and rafters, with engineered timber products such as LVL and glulam used where longer spans or higher loads are needed. Timber framing is designed to AS 1684, which provides span tables and a clear compliance pathway under the National Construction Code.
Carpenters can cut and adjust timber easily on site, which is part of why it remains popular and fast to assemble.
Light gauge steel vs timber: side-by-side
| Light gauge steel (LGS) | Timber | |
| Upfront cost | Often higher | Usually lower |
| Long-term value | Low maintenance, durable | Requires ongoing pest/moisture care |
| Termites | Not a food source for termites | Susceptible; needs treatment & management |
| Fire | Non-combustible | Combustible; lower fire resistance |
| Dimensional stability | Won't warp, shrink or twist | Can warp/shrink with moisture |
| Long spans | Strong strength-to-weight | Possible with engineered timber (LVL) |
| Thermal | Conductive; needs thermal breaks | Naturally insulating |
| Build speed | Precise, fast to erect | Fast, flexible on site |
Neither system is universally better — each suits different sites and priorities. Both must comply with the NCC, and both rely on proper engineering to perform.
Termites and moisture
In termite-prone areas, steel has a clear advantage: it isn't a food source, so it removes timber from the frame as a target. (Overall termite management under the NCC still applies to the whole building.) Steel also won't rot, which matters in damp conditions. Timber can be treated and protected, but treatment doesn't remove the need for ongoing pest inspections and maintenance.
Fire and bushfire
Steel is non-combustible, meaning it doesn't add fuel to a fire — a meaningful consideration in bushfire-prone areas, where BAL (Bushfire Attack Level) ratings drive design. That said, overall fire performance depends on the complete wall and ceiling system, not the frame alone.
Dimensional stability and finish quality
Because steel doesn't warp, shrink or twist the way timber can with moisture changes, it helps keep plaster, cladding and cabinetry aligned — which can mean cleaner finishes, particularly on larger or multi-storey builds.
Thermal performance
Steel is thermally conductive, so steel frames need thermal breaks to prevent thermal bridging (heat transferring through the frame). Timber is naturally more insulating. With correct detailing and insulation, both systems can achieve the required thermal performance.
Which should you choose?
If your priorities are termite resistance, fire performance, dimensional stability and low long-term maintenance — especially on a build with long spans or complex geometry — light gauge steel is a strong fit. If lower upfront cost, natural insulation and on-site flexibility matter most, timber may suit better.
Whichever you choose, the frame is only as good as its engineering. LGS in particular depends on accurate structural design and detailing to perform and to satisfy your building surveyor.
QED Consulting Engineers specialises in light gauge steel structural design and detailing for residential and commercial builds, working with builders and fabricators across Melbourne and beyond.
Building with light gauge steel? Talk to a Melbourne structural engineer for structural design, shop drawings and certification.
Frequently asked questions
Is steel framing better than timber? Neither is universally better. Steel offers termite resistance, fire performance and dimensional stability; timber offers lower upfront cost, natural insulation and on-site flexibility. The best choice depends on your site and priorities.
Is light gauge steel more expensive than timber? Steel is often higher in upfront cost, but it can offer better long-term value through durability, termite resistance and lower maintenance. The overall figure depends on your design, so compare quotes for the same project.
Does light gauge steel rust? LGS uses galvanised steel to resist corrosion. With correct specification and detailing, rust is well managed in normal residential conditions.
Is steel framing good for termites and bushfire? Steel isn't a food source for termites and is non-combustible, which are advantages in termite-prone and bushfire-prone areas — though whole-of-building termite and fire measures still apply.
Do I need an engineer for a steel-framed house? Yes. Light gauge steel framing relies on structural design and detailing to Australian Standards, and your building surveyor needs this documentation for the permit.
