You own a commercial building. Do you know what it would cost to rebuild it today?

Quick answerFive covers do most of the work for a building owner: damage to the building itself, loss of rent while it cannot be tenanted, your legal liability as the property owner, breakdown of the machinery that runs the building, and glass. Around them sit the quieter risks that decide claims: a sum insured nobody re-tested, a roof nobody looked at, and a disclosure nobody updated.

Damage to the building. Fire, storm, impact, water. The cover is only as good as the sum insured behind it: insure below about 80 per cent of the true rebuild cost and a co-insurance clause can scale a partial claim down, and on a total loss every dollar between your sum insured and the real rebuild cost is yours. The full mechanics are in The Co-Insurance Clause: What Every Building Owner Must Know, and the fix is on Desktop Building Replacement Valuation.

Loss of rent. If the building cannot be tenanted after an insured event, the rent stops but the loan repayments do not. This cover has two dials, how much it pays and for how long, and both have to be set for a worst-case rebuild, not a hopeful one. Our default in practice is an 18 month indemnity period, we recommend 24 wherever we can, and 12 is a floor we only place on a client's express instruction. Rebuilds run long: demolition, approvals, consultants, builders' lead times.

Property owners liability. The one owners never think about until it is too late. If something about your building injures someone or damages a neighbouring property, a collapsing wall, a failure that spreads next door, the legal liability can be yours personally as the owner. It is a separate cover from your tenant's public liability, and the two do not substitute for each other. See Property Owners Liability.

Equipment breakdown and glass. The lifts, air conditioning and switchboards that make a building tenantable, and the glass that a landlord is usually responsible for under the lease. Small covers, cheap to include, and exactly the sort of thing an apples-for-apples quote quietly drops.

The roof. The part of a commercial building we see argued about most at claim time. Insurers increasingly review dated aerial imagery before paying storm claims, looking for rust, ponding and patch repairs that suggest the damage was gradual rather than sudden. We look first: more than 1,200 roof condition checks a year across our clients. See Roof Condition Monitoring.

Disclosure. The quietest risk of all. EPS sandwich panel in the walls, an asbestos roof, a tenant who changed what they do, a renovation the insurer never heard about. If the insurer would not have taken the risk had it known, a claim can fail entirely, and no premium, high or low, fixes that. Telling us is enough; making sure the insurer knows, and the policy still fits, is our job.

Queensland-specific. In the north, cyclone: if your building's sum insured is under $5 million assessed across all locations on one policy, you may benefit from reduced cyclone premiums through the federal Cyclone Reinsurance Pool; insurers subscribed to the pool apply the reduction automatically in their pricing. Everywhere, flood: usually a named peril with its own sub-limit and excess, and worth confirming rather than assuming, whichever way you want the answer to go.

Quick answerEvery building owner needs the fundamentals above. What changes with your situation is the structure around them, and structure is where the expensive mistakes hide.

• You lease the building to tenants. Your rent is an income stream, your lease decides who insures what, and if you hold more than one property, a single underinsured claim can ripple into loan covenants across the lot. Start at For Commercial Property Owners and Commercial Landlords Insurance.
• You run your own business from your building. You carry two risks that fail together: the building and the livelihood inside it, often held in two different entities, which is exactly where cover breaks. Start at For Business Owner-Occupiers.
• You own a lot in a strata scheme. The body corporate insures the common property; what you own inside your lot still needs its own cover, and the gap between the two catches people. Start at Commercial Strata Insurance.
• You are actually the tenant, checking on your landlord's cover. Smart move, and yes, it matters to you. Start at For Business Owner Tenants.

Here is the smallest useful thing you can send us, and it is smaller than most people expect. Send the page of your schedule that lists what is insured and for how much. You do not need to send us the price to start. From that page alone we can usually tell which product you are on and which insurer stands behind it, and from there we can pull the actual wording and read what it would and would not pay, before we talk about a number. Send the price as well if you would rather, and we will look at both. That question, what your policy would actually do, is the one most owners have never had answered. If you are in good shape, we will say so.