Steel Frames
Termite damage costs Australian homeowners several hundred million dollars a year by conservative estimates, and it is not covered by a standard home and contents insurance policy. The frame is usually where the real cost lives, because a subterranean termite colony can work through structural timber for years before anyone notices anything wrong. A steel frame does not remove every termite consideration from a build, but it removes the frame itself from the equation entirely, since termites cannot eat steel. This guide covers how termites actually damage a home, what the research says about the cost, what Australian Standards require regardless of frame material, and where a steel frame genuinely changes the picture.
Subterranean termites, the species responsible for the overwhelming majority of structural damage in Australian homes, live in underground colonies that can hold many thousands of individuals and travel to a food source through soil or self built mud tubes that shield them from light and predators. Timber wall framing, roof framing and flooring are cellulose, which is exactly what termites eat. Because the damage happens inside wall cavities and roof spaces, a colony can be active for years before it shows up as a sagging floor, a sticking door, or a hollow sound when timber is tapped. By the time damage is visible, the structural member has often lost a meaningful share of its load capacity, which is why so much of the cost associated with termites is repair rather than prevention.
Australia is home to over 350 known termite species, though only a small number of these are responsible for the structural damage homeowners actually encounter. The behaviour that makes them costly is consistent across the damaging species: they do not eat visibly from the outside, they hollow timber out from within, following the grain and avoiding painted or hard outer surfaces for as long as possible, which is precisely why a professional inspection, rather than a visual check by an untrained eye, is the standard recommendation.
This is what makes termites different from most other risks a home faces. A leak or a crack is usually visible early. Termite damage to a timber frame is designed by nature to be hidden, which is precisely why the financial and structural consequences tend to be larger than homeowners expect.
Estimates of the national cost of termite damage vary depending on the year and the methodology, which is worth being upfront about rather than quoting a single number as gospel. CSIRO backed research cited by Archicentre Australia has put the figure as high as several hundred million dollars a year in direct repair costs, while later industry studies commissioned by pest management bodies have put the combined national cost of treatment and repair into the billions once compliance and prevention work is included. What the various studies agree on consistently is the part that matters most to a homeowner: termite damage is generally excluded from standard home and contents insurance, so the repair bill for a serious infestation falls on the owner directly, and a documented termite history can also reduce a property’s resale value.
It is worth being clear about something a lot of marketing around termite resistant materials glosses over: Australian Standard AS 3660.1, Termite management, New building work, requires a termite management system on essentially every new residential building, regardless of what the frame is made of. That system is typically a physical barrier (such as graded stone or a termite resistant membrane at slab penetrations and edges), a chemically treated zone, or termite resistant construction, and it is referenced through the National Construction Code rather than being optional best practice. A steel frame does not exempt a project from AS 3660 compliance. What it changes is what happens if a termite colony gets past that management system and reaches the frame itself.
Steel is not cellulose, and termites have no ability to digest it. A structural member made from cold formed steel is, from a termite’s perspective, simply not food, which means there is no mechanism by which a termite colony can cause the kind of structural section loss that makes timber frame termite damage so expensive to fix. This is not a CMC marketing claim invented for this article. BlueScope, the manufacturer of TRUECORE® steel, states plainly that TRUECORE® steel is 100% termite and borer proof, and does not need chemical timber treatments to achieve that. It is a genuine, well established material property of steel framing generally, not something specific to one brand.
It is also why steel framing does not need the chemical timber treatments (the H2 and H3 treated pine classifications many builders will be familiar with) that timber frames rely on for at least some pest resistance. There is nothing to treat, and nothing that degrades over time the way a chemical barrier in timber can as the wood weathers or is cut and drilled on site, exposing untreated core timber.
This is the part worth being direct about, because overstating what steel framing solves is not doing anyone a favour. A steel frame removes termite risk from the structural frame itself. It does not remove termite risk from the rest of the building. Most homes, steel framed or not, still include timber somewhere: subfloor bearers and joists in some construction types, architraves, skirting boards, door and window joinery, timber decking, fencing, and landscaping timber. Any of that remains a genuine termite target, and a full AS 3660 compliant termite management system covering the whole site is still the standard, sensible approach, not an optional extra because the frame happens to be steel.
The honest way to describe the benefit is this: a steel frame takes the single most expensive and hardest to detect category of termite damage, structural frame loss, off the table, while the routine site wide termite management every Australian home needs continues as normal.
Termite pressure is not uniform across Australia, and CSIRO hazard mapping shows real regional variation, generally trending higher in warmer and more humid parts of the country. Victoria, including greater Melbourne, sits in a lower pressure band than tropical and subtropical states, but lower pressure is not the same as no pressure, and established suburbs with older gardens, retained timber, and mature trees can still carry active termite colonies. CMC Steel Solutions frames residential, commercial and childcare projects across Melbourne and Victoria, and termite exposure is one of the practical, site specific questions worth raising with your building surveyor or a licensed pest inspector regardless of which suburb a project sits in.
A physical termite barrier, most commonly graded stone aggregate or a purpose made termite resistant membrane installed at slab edges and around every penetration and pipe entry, works by blocking the concealed access routes termites need to reach a building undetected. A chemical barrier does the same job using a treated zone in the soil around and under the slab. Both approaches are installed before the frame goes up, and both remain the standard, expected approach on a steel framed project just as they would on a timber framed one, since the barrier is protecting the whole building envelope, not just whichever structural material happens to be used above it.
Where a steel frame changes the ongoing picture is at inspection time. Standard advice for any Australian home, regardless of frame material, is a termite inspection at least once every twelve months, and more frequently in higher risk areas. On a timber framed home, that inspection is partly about catching frame damage early, before it becomes structural. On a steel framed home, the inspection still matters for the barrier itself, the subfloor if timber is present, and any timber joinery, but the single biggest and most expensive failure mode, an undetected colony working through structural studs and trusses for years, simply is not on the table in the same way.
Key Takeaways
Timber Frame Compared With Steel Frame: Where Termite Risk Actually Sits
Element | Timber frame | Steel frame |
Structural studs, plates, trusses | Cellulose material, a genuine termite food source if barriers fail | Not cellulose, cannot be structurally damaged by termites |
Chemical treatment of the frame | H2 or H3 treated pine typically required | Not required, steel has no cellulose to protect |
Whole of site AS 3660 barrier | Required | Still required |
Timber joinery, decking, fencing | Termite target either way | Termite target either way |
Detection difficulty | Hidden in wall and roof cavities for years | Not applicable to the frame itself |
The steel structural frame itself cannot be eaten or structurally damaged by termites, since it contains no cellulose. This is a genuine material property, confirmed by BlueScope for TRUECORE® steel specifically. It does not mean a steel framed home is immune to termites finding their way into timber elements elsewhere in the building, such as joinery, decking or fencing.
Yes. AS 3660.1 termite management requirements apply to new residential buildings regardless of frame material, and this is typically addressed at slab and footing stage before framing begins.
Industry research consistently links a documented termite history to reduced buyer confidence and lower resale value, separate from the direct cost of repairs, since termite damage is not something most insurance policies will have already covered.
Chemical treatments such as H2 and H3 rated pine exist to make cellulose less attractive or accessible to termites. Steel contains no cellulose in the first place, so there is nothing for a chemical treatment to protect.
No. CSIRO hazard data shows termite pressure varies regionally and is generally influenced by climate, established vegetation and site history. A licensed pest inspector or your building surveyor can advise on the specific risk profile for a given site.
Termites can still travel through or nest within wall cavities in a steel framed building, since the cavity itself is just an empty space, but they cannot consume or structurally weaken the steel members forming that cavity the way they can with timber.
TRUECORE® steel is one of the steel products CMC Steel Solutions may specify for a project. Another steel brand or grade may be better suited depending on the specific requirements, so this is confirmed with our team at the design stage rather than assumed.
If termite exposure is a factor in your site selection or your choice of framing system, our team can talk through how light gauge and structural steel framing fits your project alongside your AS 3660 termite management obligations.
Call CMC Steel Solutions on 1300 285 566, email info@cmcsteelsolutions.com.au, or contact us online to discuss your project.