Building your own home is an exciting undertaking — but financing a build works very differently from buying an existing property. Instead of a single lump-sum settlement, a construction loan releases funds in stages as the build progresses, matching the builder’s payment schedule.
What Is a Construction Loan?
A construction loan is a short-term finance facility that:
- Releases funds in progress payments (drawdowns) as each stage of the build is completed
- Charges interest only on the amount drawn down, not the full approved amount
- Converts to a standard term mortgage once the build is complete
During construction, you pay interest only on the drawn balance. This is typically lower than full mortgage repayments — but your costs during this period also include rent (if renting while building), which is why the build-and-rent period can put pressure on cash flow.
How Progress Payments Work
Most NZ construction loans use a stage-based drawdown structure aligned with your building contract. Typical stages:
| Stage | Approximate % of contract value | What triggers the drawdown |
|---|---|---|
| Land purchase | As required | Settlement on section |
| Slab / foundation | 10–15% | Foundation/slab completion |
| Frame | 10–15% | Frame erected and signed off |
| Lock-up | 15–20% | Exterior walls and roof complete |
| Interior fit-out | 15–20% | Interior linings and fit-out complete |
| Practical completion | 30–40% | Code of Compliance Certificate (CCC) |
Before releasing each drawdown, the bank typically requires:
- A valuer’s progress inspection confirming the stage is complete
- Confirmation the work matches the approved building contract
- No outstanding progress claims from the builder
Progress inspection fees ($150–$350 per inspection) add to the cost of a construction loan — budget for 5–6 of these over a standard build.
LVR Rules for Construction Loans
Construction loans are treated more favourably under the RBNZ’s LVR restrictions:
- Owner-occupiers: Construction loans are exempt from the standard 80% LVR cap. You can borrow up to 90% of the as-completed value (10% deposit)
- Investors: Construction loans are exempt from the 65% investor LVR cap; 80% LVR (20% deposit) is available on new builds
The “as-completed” value is determined by a registered valuer based on the approved plans and specifications before construction begins. This is the value the bank lends against — not the land value.
Important: The valuation must support the contract price. If the valuer assesses a lower “as-completed” value than the build cost, the bank will only lend against the lower figure, and you’ll need to cover the gap with additional equity or cash.
Costs and Rates
Interest rate: Construction loans typically use the floating rate for the construction period, as the drawdowns are variable in timing and amount. Some banks offer fixed rates for the construction period.
As at April 2026, floating rates are approximately 7.09%. The floating rate applies only to the drawn balance, so early in the build (when little has been drawn) the interest cost is low.
Example interest cost during construction (12-month build):
- Total build contract: $850,000 (land + build)
- Average drawn balance during build (midpoint assumption): $425,000
- Rate: 7.09%
- Approximate interest during construction: $425,000 × 7.09% = $30,133
This is in addition to any rent you’re paying while building.
Conversion to term mortgage: Once the CCC is issued, the construction loan converts to a standard mortgage. At this point, you can choose your fixed/floating/split structure, term, and repayment approach — just like any other mortgage.
Additional fees:
- Progress inspection fees: $150–$350 × 5–6 stages = $750–$2,100
- Valuation (as-completed): $600–$1,200
- Legal fees for construction contract review: $1,500–$3,000
- Building consent and council fees: varies by council and project size
What the Bank Needs to Approve a Construction Loan
Before approving a construction loan, the bank requires:
- Signed building contract with a registered NZ builder/building company (licensed building practitioner)
- Approved building consent from the local council
- Registered valuation of the as-completed value
- Fixed-price contract — most banks require a fixed-price contract to limit cost-blowout risk
- Evidence of your equity/deposit (usually the land if you already own it, or confirmed land purchase)
- The usual income and liability evidence (same as a standard mortgage application)
Fixed-Price Contracts: Why Banks Require Them
Banks strongly prefer (and usually require) a fixed-price building contract — meaning the builder takes on the risk of cost overruns. The bank doesn’t want to be asked for more money partway through a build because costs have escalated.
If the builder won’t provide a fixed-price contract, or if you’re acting as your own project manager (owner-builder), bank lending is harder to obtain and often requires much larger equity (40–50% in some cases).
Provisional sums are common in building contracts and represent items where the exact cost isn’t yet determined (e.g., landscaping, site-specific earthworks). Banks will include provisional sums in the total loan but monitor whether final costs are within the budget.
Key Risks in Construction Lending
Cost overruns: Even with a fixed-price contract, changes you request (variations) add cost. Maintain a contingency of 10–15% of the build cost.
Builder failure: If your builder becomes insolvent mid-build, you may be left with a partially complete property and a legal dispute. Building guarantees (e.g., Homefirst from Certified Builders) provide some protection. Check whether your builder has current guarantees.
Delays: Delays extend the construction period, increasing floating interest costs and the period of double costs (construction interest + rent).
Valuation gap: If the as-completed value comes in below the contract price, you’ll need additional equity. Get an independent valuation early rather than relying solely on the bank’s valuer.
Construction Loan vs New Build Purchase
An alternative to a construction loan is purchasing a new build off the plans from a developer. In this case:
- You pay a deposit (typically 10%) when signing the Agreement for Sale and Purchase
- The balance is due on completion (settlement)
- You get a standard mortgage — not a construction loan — at settlement
- You avoid the progress drawdown complexity and builder-direct relationship
Purchasing off-plan is simpler but offers less control over specifications and timing. See New Build Mortgage NZ for the off-plan purchase route.
Further Reading
- New Build Mortgage NZ — buying a new build (off-plan)
- New Build LVR NZ — LVR rules for new builds
- Building Finance NZ — overview of all building finance options
- Getting a Mortgage in NZ — the standard mortgage application process
- Mortgage Hub — all NZ mortgage guides