House and contents insurance in Australia: the sum insured trap, and what your policy actually covers

Most Australian house and contents policies are underinsured by 20-40%. The owner picks a sum insured that matches what they paid for the place, not what it costs to rebuild, and the rebuild cost has compounded 6-9% a year through the post-COVID construction-cost spike. When a fire claim comes in and the rebuild quote lands above the sum insured, the insurer applies the average clause and pays out the same proportional shortfall on partial claims too. The household discovers the gap only when the assessor's report arrives.

Home insurance in this country is sold as a commodity and priced as a risk product, and the gap between those two framings is where most disputes live. The policy document runs forty pages. The certificate of insurance runs two. Almost nobody reads the first; almost everybody relies on the second. The cost of that asymmetry only shows up at claim time.

House cover vs contents cover vs landlord cover

Australian home policies split into three product families that look similar on the front page and behave differently on the back.

• House (building) insurance covers the structure itself: walls, roof, floors, fixed wiring and plumbing, kitchens and bathrooms as installed, built-in wardrobes, fences, retaining walls, driveways, and usually outbuildings such as garages, sheds and granny flats up to a sub-limit. Solar panels, pool fencing and septic systems are typically included; pools themselves are sometimes a separate item.
• Contents insurance covers anything that would fall out if you turned the house upside down: furniture, electronics, clothing, kitchenware, jewellery, sporting equipment, tools, food in the freezer. Most policies have category sub-limits, and high-value items above the sub-limit must be specified and often individually valued.
• Landlord insurance is structurally similar to building cover but designed around a tenanted investment property, with optional add-ons for rental default, malicious tenant damage, and loss of rent during repair periods. A house policy on a rented property typically excludes those tenant-driven losses; if the property is investment-grade, see the dedicated landlord insurance guide for what the PPOR product won't cover.

Combined home and contents policies bundle the first two and usually discount the combined premium 5-15% relative to buying them separately. The two sums insured remain distinct on the certificate and are assessed independently at claim time.

How to set the building sum insured

Replacement cost is not the same as market value, and market value is not the same as purchase price. The number the policy needs is the cost to rebuild the same house, on the same block, to current building code, with the existing site cleared first. The components:

• Demolition and site clearance after a total loss: typically $30,000-$60,000 for a standard suburban block, more if asbestos is present or access is difficult.
• Design, certification and council fees: architect or building designer, structural engineer, energy rating, soil test, town planning where required. Budget 8-12% of construction cost.
• Construction at current build cost per square metre: this is the biggest line. Project-builder volume housing in outer suburbs runs around $2,400/m²; custom builds with mid-range fixtures land between $3,600 and $4,800/m²; prestige inner-city work starts at $5,500/m² and goes up from there. Cyclone-rated construction north of 26°S adds 10-15%.
• Landscaping, driveways, outbuildings and fencing: often $30,000-$80,000 for an established property.
• Contingency margin for cost overruns and rebuild-period inflation: 10-15% on top of the calculated total. Insurance rebuilds frequently run 18-30 months from claim to handover, and the build cost on month 24 is not the build cost on month one.

Most insurers offer an online calculator built on Cordell Sum Sure or a similar quantity-surveyor dataset. Westpac, SGIO and RACV all use Cordell; Suncorp uses an in-house equivalent. Feed in suburb, build year, wall and roof material, number of bathrooms, fixtures quality, pool and outbuildings, and it produces a number. Treat the calculator output as a starting point. For anything non-standard such as raised timber Queenslanders, heritage masonry, sloping blocks or bespoke architectural builds the calculator typically understates by 10-20%, and a quantity surveyor's report ($400-$800) is the cheapest insurance against underinsurance.

The average clause: why underinsurance hurts on partial claims too

This is the mechanic that most policyholders learn the wrong way. Standard Cover policies under the Insurance Contracts Act 1984 allow insurers to apply an average (co-insurance) clause when the sum insured is below the true replacement cost. If you insure for 80% of what the rebuild actually costs, the insurer pays 80% of any claim, partial or total, after the excess.

On a total loss the cap is the sum insured, so underinsurance directly determines the shortfall. On a partial loss the calculation is proportional. A $20,000 partial claim on a property insured at 80% of replacement value pays out $16,000, not $20,000, even though the actual repair cost is the same. The insurer is not paying for the loss; they are paying their proportional share of the risk they were on cover for.

Some insurers sell a “total replacement” or “guaranteed rebuild” product that waives the average clause and commits to rebuilding to the same specification regardless of sum insured. These cost 15-25% more than a standard sum-insured product, are usually capped at a maximum dwelling value, and require a full property inspection at policy inception. For higher-value properties in cyclone or bushfire-exposed postcodes the maths often works.

How to set the contents sum insured

The honest method is a room-by-room inventory. Most people skip it and end up underinsured on contents by a wider margin than on building. The realistic figure for a couple in a three-bedroom house is rarely below $80,000; for a family of four with several years of accumulation it routinely sits between $120,000 and $200,000.

• Lounge and dining: sofa, armchairs, coffee table, dining set, rugs, TV, sound, console. $8,000-$25,000.
• Bedrooms: beds, mattresses, bedside tables, wardrobes' contents, lamps. $6,000-$15,000 per bedroom for full replacement at today's retail.
• Wardrobes (clothes and shoes): $5,000-$15,000 for a couple, more if either partner has a professional wardrobe or seasonal sports kit.
• Kitchen: white goods (fridge, oven, dishwasher, washing machine, dryer), small appliances, cookware, crockery, glassware, cutlery. $8,000-$20,000 if you count it honestly.
• Office, garage, garden: computers, printers, tools, lawnmower, sporting equipment, bicycles. Easily $5,000-$20,000.
• Decor, art, books, hobby gear: $3,000-$15,000 in most households.

Sub-limits are the next trap. Standard policies cap jewellery and watches at $1,500-$3,000 per item, art and collectables at similar levels, computers at around $5,000, sometimes bicycles at $1,000-$2,000. An engagement ring, a single high-end laptop, a road bike, a guitar collection, or a stamp album can each blow through the default cap. Specify them on the schedule with a current valuation; the premium uplift is usually small relative to the coverage gap.

Flood, cyclone, bushfire and storm: what the exclusions actually say

The 2008 Black Saturday and 2011 Brisbane flood claim experiences led to a regulatory cleanup. Most policies now share standardised definitions, but the cover varies sharply by insurer and by postcode.

• Flood: defined in the Insurance Contracts Regulations as water from rivers, creeks, lakes or other natural watercourses escaping their normal confines. Most policies now include flood by default after the 2012 standard-definition reform, but flood-zone postcodes often carry a separate flood excess of $2,000-$5,000 or higher, and a 72-hour wait period after policy start during which a flood claim is not payable. Some insurers offer flood as opt-in rather than default; check the schedule, not the marketing.
• Storm and storm surge: storm cover is standard. Storm surge (seawater driven inland by cyclonic wind) is a separate definition and is frequently excluded or sub-limited. In cyclone zones this is the line item that decides whether a coastal property is meaningfully covered.
• Cyclone: covered under storm. North of 26°S in WA, NT and QLD the premium loading is substantial, the excess on cyclone claims is typically $1,000-$5,000 above the base excess, and some insurers require a building survey before binding cover.
• Bushfire: covered under fire. A 48-72 hour cooling-off applies after a total fire ban declaration or active fire warning in your area, to prevent buying-on-fire-warning. New policies bound during this window will not cover fire damage from the existing event.
• Actions of the sea, erosion, landslide: generally excluded outright. Properties on coastal cliffs, eroding foreshores, or above active landslide zones face genuine uninsurability for those perils.

What drives the premium

Insurers price at the postcode-and-property level, not the suburb level. The main drivers:

• Postcode risk: flood-zone mapping, cyclone exposure, bushfire BAL rating, crime statistics for theft and malicious damage.
• Building age and materials: full double-brick masonry on a concrete slab prices lower than brick veneer, which prices lower than full weatherboard. Pre-1980 wiring and pre-1990 plumbing attract loadings on older homes.
• Security: monitored alarm, deadlocks on external doors, key-operated window locks, garage with internal access. Each shaves a few per cent.
• Excess level: lifting the standard excess from $500 to $2,000 typically drops the premium 10-20%. Make sure the chosen excess is genuinely affordable at claim time.
• Sum insured level: premium scales close to linearly with sum insured. The incremental cost of insuring for the true rebuild rather than 60% of it is almost always smaller than the average-clause shortfall on a single mid-sized claim.
• Claims history: prior claims in the last three to five years lift the renewal price and can trigger declinature at some insurers.

A worked example: Brisbane timber house, flood-prone street

A 1960s raised timber Queenslander, 180 m², on a block in a known flood-overlay street. The owners purchased for $850,000 and insured the building at $400,000 on the reasoning that “the land is most of the value”. The contents schedule sits at $60,000.

The true replacement cost calculation:

• Construction: 180 m² × $3,400/m² for a mid-spec custom rebuild = $612,000.
• Cyclone-rated construction uplift (Brisbane sits just inside the cyclone-influence band for some insurers): 15% × $612,000 = $91,800. Subtotal $703,800.
• Demolition, site clearance, design fees, council certification, landscaping and driveway replacement, carport rebuild: approximately $50,000.
• True rebuild estimate: roughly $754,000.

A flood comes through in 2026 and damages the kitchen, the downstairs bathroom and the ground-floor flooring. The repair quote lands at $80,000. The insurer applies the average clause: $400,000 / $754,000 = 53% underinsurance ratio. The payout is 53% × $80,000 = $42,400, minus the flood excess. The owner's shortfall is approximately $37,600 plus excess before the kitchen is back in operation.

On the same property insured at $754,000, the insurer pays the full $80,000 repair less the standard excess. The annual premium difference between insuring at $400,000 and insuring at $754,000 in a Brisbane flood postcode runs around $300-$500 a year. Saving $300 a year for five years to lose $37,600 on a single mid-size claim is the average-clause trap in one line.

The PDS sections worth actually reading

Forty pages is too many. Five sections do most of the work.

• Definitions: how the policy defines flood, storm, storm surge, actions of the sea, escape of liquid, accidental damage. The same word means different things at different insurers.
• What we cover: the positive list of insured events. If a peril is not on this list, it is not covered, even if it isn't explicitly excluded later.
• What we don't cover: the exclusions. Pay special attention to gradual damage, wear and tear, mould, vermin, faulty workmanship, and unoccupancy clauses (most policies suspend cover after 60-90 consecutive days of vacancy unless agreed).
• Sub-limits and special conditions: the per-item caps on jewellery, electronics, collectables; the limits on outbuildings, fences, retaining walls; the conditions attached to home office equipment and tools of trade.
• Claims procedure and excess schedule: how a claim is notified, the documentation required, the standard excess and any additional event-specific excesses (cyclone, flood, named-storm).

Buying, renewing, and reviewing

At purchase, the sum insured needs to be set before settlement so the building is covered from the day contracts go unconditional or the day risk passes (the date varies by state). Use the insurer's replacement calculator, then add a quantity surveyor review for anything older than 30 years or with non-standard construction. Factor the annual premium into the total carry-cost on the buying cost calculator alongside rates, strata and mortgage repayments.

At renewal each year, two checks. First, the renewal notice will usually escalate the sum insured by a construction-cost index (commonly 4-6%); compare that to what the calculator actually says and adjust upward if building costs in your area have run faster. Second, review contents for additions and disposals over the past year, and refresh specified-item valuations every three to five years on jewellery, art, and collectables.

After any major change, redo the calculation. A renovation, a granny-flat addition, a pool, a fence replacement, or a knockdown-rebuild project all change the sum insured materially, and most of them change it during a period when the property is vulnerable. Builder's all-risk insurance covers the construction site itself; the homeowner policy needs to be aligned for the day-after-handover state of the property. For costs around the move-in itself, the moving-cost checklist runs through the line items most household budgets miss.

The questions that decide most claims

Three questions, asked before binding cover, would prevent most of the disputes that end up at the Australian Financial Complaints Authority.

• Is the sum insured based on a current rebuild calculation, not on purchase price or market value?
• Does the policy include flood, storm surge, and actions of the sea on the schedule, and what are the excesses for each?
• Are all high-value items above default sub-limits specified individually on the schedule, with current valuations on file?

A policy that answers those three correctly will not prevent every dispute, but it removes the structural reasons most claims pay out below the policyholder's expectation. The premium difference between a well-specified policy and an under-specified one is typically a few hundred dollars a year; the claim difference can run into the tens of thousands on a single event.