Costs outside the building contract
A building contract prices the building. A project costs more than that, and the gap is where most budgets come unstuck — not through anyone’s fault, but because nobody listed it.
Why this list matters
When you compare quotes, you are comparing what each builder has included. What none of them include is still yours to pay. The point of this list is to get those items into your budget before the contract, so the contract figure is not mistaken for the project figure.
Every project is different, and some of the items below may be inside your contract rather than outside it. The only way to know is to read the inclusions and exclusions line by line and ask about anything that is not named.
Before a shovel goes in
- Design. Architect or building designer, and interior design if you want it.
- Consultants. Surveyor, geotechnical engineer, structural and civil engineers, and, depending on the site, arborist, bushfire, flood, heritage or traffic reports. Your planning certificate tells you which constraints apply and therefore which reports you are likely to need.
- Approval fees. Council DA fees or a private certifier’s fees for a CDC, plus the construction certificate, inspections and occupation certificate.
- Levies and contributions. Councils may charge development contributions, and in NSW a Long Service Levy is payable on building work above a set threshold before the construction certificate is issued. Ask your council and certifier for the current amounts; they change.
Getting the site ready
On a knockdown rebuild, demolition, asbestos removal where present, and the disconnection of existing services may sit inside the building contract or outside it. Find out which.
New or upgraded connections to water, sewer, power and data are often a separate line. The network operators set their own requirements and timeframes, and an upgrade to a larger power supply or a sewer that needs relocating can be a meaningful cost that no builder controls.
Finishing the property, not just the house
- Landscaping, driveways, fencing and paving. Frequently excluded or allowed for only at a basic level.
- Pools. Usually a separate scope, with its own approval, fencing and certification.
- Window furnishings, loose furniture and appliances not named in the contract.
- Air conditioning, solar, security and audio-visual, which are sometimes included and sometimes left to separate trades.
Living elsewhere
Rent for the length of the build, plus a margin. Two removals and storage in between. Possibly a higher insurance premium on the place you rent. These are the costs people most often forget because they have nothing to do with the house — and they are entirely driven by how long the project runs.
Money held back for the unknown
Set aside a contingency that belongs to you, separate from any allowance in the contract. Its job is to absorb the decisions you make along the way and the conditions nobody could see in advance. Spending none of it is a good outcome, not a wasted one.
If you are borrowing, ask your lender early how they treat costs outside the building contract. Some can be financed with the build; some cannot, and it is better to know before you need the money.
A practical note
Build the list once, at the start, with real quotes against as many lines as possible. It turns a vague worry about ‘hidden costs’ into a short list of known ones. Nothing here is financial advice; your lender, accountant and council are the people to confirm the figures for your project.