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If you’ve renovated your home to make more room for a growing family, the best time to check your rebuild sum insured is now — rather than waiting until your next renewal.

In New Zealand, your sum insured is the maximum amount your insurer will generally pay towards rebuilding your home after a major insured loss, subject to your policy terms. Renovations can increase the cost of rebuilding, particularly if you’ve added bedrooms, bathrooms, living space or higher-quality fittings. House & Contents Insurance: Sum Insured ExplainedHome renovation

Here’s a practical way to check whether your cover is still enough.

1. Recalculate your home's rebuild cost

Start with the home you have now

Check your current policy schedule and note the existing sum insured. Then update your home's details to reflect the completed renovations, including any extra floor area, bedrooms, bathrooms, storeys and changes to construction quality.

Use a rebuild cost calculator

Try the free Cotality Sum Sure calculator, available through many New Zealand insurers. Enter your home's current details rather than relying on an old estimate. Use the calculator provided or recommended by your insurer where possible.

Include the costs beyond the house itself

Check whether the estimate allows for demolition, debris removal, professional fees, consents, GST where applicable, and relevant features such as decks, driveways, fences, retaining walls and garages.

You can start with the Insurance Council of New Zealand's sum insured guidance and your insurer's calculator. Home Sum InsuredHouse & Contents Insurance: Sum Insured Explained

2. Check whether your renovations are fully reflected

Use this checklist to make sure nothing has been missed.

Rebuild review checklist

0 of 7 checked

Added floor area, bedrooms or bathrooms

Renovated kitchen, bathrooms and fixed fittings

Higher-spec materials or bespoke architectural features

Garage, sleepout, deck, patio or other additions

Driveways, fences, retaining walls and other outdoor structures

Demolition, debris removal, professional fees and consents

Possible increases in building costs during the insurance period

3. Decide whether you need a professional estimate

An online calculator is a useful starting point, but consider getting a rebuild assessment from a quantity surveyor or registered property valuer if you have:

• Added a substantial extension or another storey.
• Used expensive or non-standard materials and finishes.
• A steep or difficult-to-access building site.
• Significant retaining walls or other features that may need separate cover.

Ask your builder for the renovation plans, final floor area and specifications to help with the assessment. Remember that what you spent on renovations is not necessarily what it would cost to reconstruct them following a total loss. ICNZ Consumer Guide 2025 – Sum Insured: What it is and why it mattersHome Insurance Sum Insured - estimate rebuild costs

4. Update your insurer — don't just rely on renewal

Contact your insurer or broker and ask them to confirm:

• Your current sum insured reflects the renovated house.
• The policy covers the new floor area and features.
• Whether special features need separate cover.
• Whether GST is included in your sum insured.
• Whether your policy is based on a fixed sum insured or offers a different form of replacement cover.

Also check your contents insurance. A growing family may have accumulated more beds, furniture, appliances, clothing and children's belongings, which could leave your contents cover inadequate too. How to get the best house and contents insuranceHouse & Contents Insurance: Sum Insured Explained

Where to start

Use the Cotality Sum Sure rebuild estimate information and check whether your insurer offers access to its calculator. The estimate is a guide, not a guarantee of the actual cost to rebuild. Online Property Rebuild Cost CalculatorHome Insurance Sum Insured - estimate rebuild costs

My recommendation: recalculate using your renovated home's details, compare the result with your current sum insured, and ask your insurer to update the cover now if needed. Review it again at each renewal and after future renovations.