Understanding the risks of construction loans in Australia

Published 17 April 2026 · Updated 17 April 2026 · 6 min read · By Shane Heness, mortgage broker

Construction lending is the most complex residential product in the market, and the risks sit in different places from a standard purchase. On a normal purchase, the main risk is whether the loan settles. On a build, the loan settles easily and then twelve to eighteen months of things can go wrong.

Risk 1: the builder fails mid-build

This is the risk that costs the most and the one people plan for the least. The building industry has a higher insolvency rate than almost any other sector in Australia, and a builder collapse partway through a project is not rare.

Home warranty insurance, called Home Building Compensation Cover in NSW, is the protection, and every lender requires it before the first drawdown. What people misunderstand is how it behaves in practice.

Indicative at September 2026. Cover caps and scheme rules vary by state and change. Check the current position for your state and contract value.

How to reduce it. Check the builder is currently licensed for the contract value, ask how many jobs they have running at once, look at whether they are asking for unusually large early stage payments, and confirm the warranty certificate is issued in your name before the first drawdown rather than promised.

Risk 2: variations the lender never approved

The lender approves against the contract sum on the day of assessment. If you and the builder later agree to upgrade the kitchen, add a second driveway or change the roof profile, the contract sum goes up and the lender does not automatically follow.

That leaves two options. Pay the difference in cash, or apply to increase the loan, which means a fresh assessment at the current assessment rate and usually a fresh valuation. On a build that started eighteen months ago, a fresh assessment can produce a smaller approval than the original.

How to reduce it. Decide the specification before signing, not during. Where a variation is unavoidable, deal with the funding before the work happens rather than when the invoice arrives.

Risk 3: the as-if-complete valuation comes in short

A construction loan is secured against a house that does not exist. The valuer assesses what it will be worth on completion, working from the stamped plans, the specification and the contract.

Where that figure lands below what the borrowing assumed, the shortfall becomes cash you have to produce.

Illustrative only. Not a quote or an indication of approval.

How to reduce it. A detailed inclusions schedule. Valuers value what is written down, and a specification that says "quality floor coverings" is valued differently from one that names the product and the area. This is a free improvement that borrowers routinely skip.

Risk 4: title registration delays

In new estates, land is frequently sold before the title registers. Registration delays of six to eighteen months are routine, and they are almost entirely outside your control or the developer's.

The finance consequence is that your loan approval expires. Most approvals last 90 days. A re-approval is assessed against your position at that time: your income, your debts, the lender's assessment rate and their current policy. A job change, a new car loan, a rate movement or a policy tightening in the interim can all reduce what you are approved for, and in some cases remove the approval entirely.

How to reduce it. Ask the developer for a realistic registration estimate in writing and check it against the approval expiry before signing the land contract. Avoid taking on new debt during the waiting period. Tell your broker immediately if your employment changes.

Risk 5: holding costs run longer than budgeted

Through the build you are paying interest on the drawn balance and, usually, rent or an existing mortgage at the same time. Both of those scale with time, and builds run late far more often than they run early.

Illustrative, based on a $1.1 million facility drawn progressively at a flat 6.0 per cent interest only. Not a quote.

How to reduce it. Budget for the completion repayment figure plus your current housing cost from day one, and add four months to whatever timeline the builder gives you. If the numbers only work on the builder's own estimate, they do not work.

Risk 6: site conditions nobody tested

The ground under an established block has been there for sixty years and nobody has looked at it. Reactive clay requiring engineered footings, a sewer main running under the building envelope, rock, contaminated fill, retaining walls on a slope and protected trees are all common, and all of them are discovered after the contract in the cases where they hurt.

How to reduce it. Two documents, both obtainable before you commit and costing a few hundred dollars between them: a sewer diagram from your water authority, and a soil classification report. They routinely change the design, the price, or the decision to proceed.

The risks that are overstated

Two things people worry about more than they need to.

Interest rate movement during the build. You are only paying interest on the drawn balance, which is small for the first half of the project. A rate move of half a percent through a build costs a few thousand dollars, not tens of thousands. It matters far less than the build running late.

Progress payment mechanics. Drawdowns feel intimidating and are actually routine. Five to ten business days per claim, a valuer confirms the stage, funds release. The only reason they go wrong is nobody submitting the claim promptly, which is administrative rather than structural.

What a well-managed construction file looks like

• Fixed price contract, with the specification locked before signing.
• Soil report and sewer diagram obtained before the contract, not after.
• Home warranty insurance certificate in your name before the first drawdown.
• Five to ten per cent contingency held in cash outside the contract.
• Loan approval expiry checked against the estimated title registration date.
• Holding costs budgeted at the completion repayment plus your current housing cost, for the builder's timeline plus four months.
• Progress claims submitted the day the builder issues them, every time.

None of that removes the risk. It moves it from something that surprises you to something you priced. Our construction loans page sets out the drawdown process and what lenders require, or book a free call and we will stress test your build before you sign anything.

Frequently asked questions

Written by Shane Heness

Owner and mortgage broker at LoanBuddy, Parramatta NSW. Eight years as a mortgage broker and a property investor since 2015. Credit Representative #528658 under Australian Credit Licence #389328.