A practical guide to Brisbane home building costs

Households ask this desk for a number. They want a dollars-per-square-metre figure they can multiply by a floor area and take to a lender. That arithmetic is how people under-borrow, then strip the insulation, the fans and the landscaping to get back inside a bank valuation. A Brisbane house is priced in layers: the building above the floor, the structure that meets the ground, the preliminaries that make a site legal, and the household costs that never enter the building contract. This guide is about reading those layers. It is not a price list. Statutory fees, insurance premiums and grant amounts move; we will not pretend a figure we write today is a government constant.

If you want the items that sit outside the contract altogether, read the companion piece on hidden costs of a new home in Queensland. If you want the paper that allocates the risk of the number moving, read fixed-price versus cost-plus and how to read a Queensland HBW building contract. What follows is the costing method that should come first.

Dollars per square metre, and why they lie

A rate per square metre is an average of unlike jobs. It mixes a single-storey project home on a classified-easy pad in a growth corridor with a two-storey custom house on a Clayfield ridge. It may be calculated on gross floor area, on habitable area, or on an area that includes the garage on one quote and excludes it on another. It rarely includes the driveway, the retaining, the fence, the clothesline or the year of interest. Used carelessly, it is a way to feel informed.

Used carefully, it is a filter. If a friend built last year, ask what was in their metre rate: which area definition, which inclusions, which site class, which year of the steel and timber cycle. Then ask what they spent after handover. The gap between those two numbers is the first useful fact.

This paper will not publish a single current rate as if it were an official statistic. Industry surveys, quantity surveyors and lenders work with bands, and those bands move with labour, imported fittings, fuel, insurance and how full the subcontractors' books are. In recent Brisbane cycles, owners and estimators have talked about a lower band for relatively standard project homes on straightforward lots, a middle band for upgraded or individually amended homes, and a higher band for architect-designed or steep-site houses with a full specification. The edges of those bands shift. Treat any figure you hear at a barbecue as a rumour with a date.

What you can do, today, is decide which band you are actually in. A catalogue house on a level Class S or M site, accepted as drawn, is not in the same band as a knockdown on a Paddington slope. If a salesperson puts you in the first band while standing on the second site, the metre rate is a sales tool.

A working range for Brisbane in this cycle

Price three things separately, even if the builder later wraps them into one figure.

First, the house as a product: structure, envelope, internal finishes, services, the kitchen and bathrooms that are actually specified. This is the layer people mean when they say "per square metre." It moves with specification more than with suburb. A thin inclusions list in Ascot is still a thin house.

Second, the site: demolition if any, earthworks, retaining, drainage, slab type, service connections, scaffolding on a slope, crane or extra labour for a tight street. This layer is almost independent of how expensive the tapware is. It is why building on a sloping Brisbane block can add a civil bill that looks like a second kitchen.

Third, the preliminaries and statutory layer: builder's administration, temporary services, insurances arranged through the contract, certification, Queensland Home Warranty Insurance, and the council and distributor-retailer charges that attach to the work. Some of these appear on the builder's claim. Some arrive as a letter in your name. All of them are part of the project cost.

Add a contingency that matches your ignorance. If you have a soil test, a survey and a developed specification, a smaller contingency is rational. If you have a display-home brochure and a hope, the contingency is the quote.

Preliminaries

Preliminaries are the cost of being allowed to build. Owners skip them because they are not a room. Builders cannot skip them.

A working list includes site establishment, temporary fencing and sediment controls, temporary power and water, a site toilet, scaffolding, hoardings on a tight inner lot, skip bins, supervision time, the builder's insurance, safety systems, survey set-out, and the administration of the contract — claims, variations, supplier accounts. On a steep or inner-city site, craneage, traffic management and after-hours constraints from Brisbane City Council or a body corporate can dwarf the temporary toilet.

Ask for preliminaries as a visible part of the quote, or at least as a conversation. A lump sum that hides them is not automatically dishonest; many fixed-price jobs absorb them. It becomes a problem when two quotes are compared and one company has assumed a wide suburban lot with a ute park, while the other has assumed a Paddington stair and a crane. You will not see that difference in a metre rate.

Supervision is the preliminary that predicts the rest of the job. A full-time supervisor on a small run of houses costs more in the preliminaries and less in the mistakes. A supervisor running a dozen jobs costs less on the page. Ask how the supervision is resourced before you congratulate yourself on the cheaper preliminaries line.

Site costs

Site costs are where honest quotes diverge. A soil classification under AS 2870 sets a foundation approach. Class A and S sites on controlled ground are the easy end. Class M, H1, H2 and E — common on SEQ clays — stiffen the raft or introduce piers. Class P, for uncontrolled fill, mine subsidence, soft ground or other problem conditions, is a designed solution. None of these is a moral failing of the lot. All of them have a price, and the price is not the display-home slab.

Rock, seepage, old septic tanks, buried demolition rubble and live services in the wrong place are latent conditions. A fixed-price contract will say who pays when they appear. Read that clause. A quote that has never seen a soil test is an invitation to meet those conditions later, as a variation, at a moment when you have no leverage.

Stormwater and sewer are site costs with legal edges. A lawful point of discharge, an upgraded sewer connection, a pump-out system, or work inside an Urban Utilities easement can be a five-figure or six-figure line depending on the land. Power upgrades and the relocation of an Energex service are in the same family. Do not let them sit inside a single hopeful "connections" allowance.

Retaining and boundary works belong here, not in a future landscaping budget. If the house cannot be occupied without a wall, the wall is part of the house. Price it with engineering, drainage and a finish, or admit that the quote is incomplete.

PC items and provisional sums

Prime-cost items and provisional sums are the contract's way of saying "we have not really priced this." Used sparingly, they are honest: a tile the owner has not chosen, a light fitting still being specified. Used generously, they are how a headline price is kept in a brochure band.

A PC item is an allowance for a product — a tap, an appliance, a sanitary fixture — that you will later select. If you select above the allowance, you pay the difference plus, often, a margin. If the allowance was never realistic, the difference is the real specification. Ask for current showroom prices against every PC line. Replace fantasy allowances with specified products before you sign, or accept that the contract price is a deposit on a larger number.

A provisional sum is an allowance for work, not just a product: rock excavation, retaining, cabinets that have not been drawn, a stormwater solution that has not been designed. These are risk. A large provisional sum on a known slope is not a quote for the slope. It is a postponement. Push known work into a fixed figure. Leave provisional only what cannot yet be known, and write down why.

When you compare two quotes, add a realistic outcome to every PC and PS line. The quote with the higher headline and the honest allowances is often the cheaper job.

How to compare two quotes

Do not start with the total. Start with whether both builders have priced the same drawings, the same specification and the same site information. If one quote is based on a display plan and a standard list, and the other on a custom drawing set, they are not competitors. Get them onto the same pack, or stop comparing them.

Make a schedule. Area definition. Number of fixtures. Ceiling heights. Insulation. Air-conditioning. Hot water. External finishes. Floor finishes. Joinery. Appliance brand and model if specified. Slab type. Retaining. Stormwater. Sewer. Preliminaries. PC items. Provisional sums. Exclusions. Construction period. Supervisor. Deposit and progress schedule. Warranty insurance notification. That schedule is tedious and it is the work.

Then read the exclusions. "Landscaping by owner," "driveway by owner," "fencing by owner," "retaining by owner," "connections by owner," "rock excluded," "council charges by owner" can remove a slice of the project that a household still has to fund. A cheaper quote with a longer exclusions list is not cheaper. It is earlier.

Beware the quote that is dramatically low. In a tight labour market a low number is usually missing scope, missing preliminaries, or a company that needs a job to keep a trade crew together. Beware also the quote that will not be held for a defined period. Costs move; a fourteen-day validity on an un-tendered display plan is ordinary. A refusal to reissue a price after you have supplied a soil test is not.

If the gap remains large after the scopes match, ask each builder to explain the gap in a paragraph. The useful answers name a structural system, a finish, or a programme assumption. The useless answers name their own quality in the abstract.

The contract that sits under the number

A price is not enforceable until it lives in a contract with a scope. The ordinary Brisbane instruments are the HIA and Master Builders residential forms, and sometimes a QBCC form. They are not interchangeable in their schedules, even when they look related. Have a construction solicitor read the one you are actually being asked to sign. The cooling-off rules on a regulated residential contract are a statutory safety net, not a substitute for that reading.

Look at how the price can change: owner variations, latent conditions, delays, prime-cost adjustments, provisional-sum adjustments, statutory fee changes. Look at the progress claims and at practical completion. A number that is "fixed" but sits on a payment schedule that fronts the cash and on a completion definition that lets the builder claim before the house is liveable is a number with conditions.

Queensland Home Warranty Insurance attaches to eligible work once the contract is notified and the premium is paid. The premium is a scale, and the scale moves. Ask who notifies, who pays, and when. Do not confuse the statutory policy with a promise that the company is financially calm.

The costs and contracts hub is the rest of this desk. The method, if you want it in one paragraph, is this: survey and soil first; a specified brief; two or three prices on the same pack; a schedule that makes the prices comparable; a contract that says what happens when the ground or your mind changes. If you want the institutional voice behind that method, it is in our about page. The number you can defend is the number you have unpicked. The number you can only repeat is the one that will move.