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10 Most Common Hidden Costs of Building a Custom Home

10 Most Common Hidden Costs of Building a Custom Home

For many of us, designing a home based around our own vision and lifestyle is a huge drawcard. But even with an estimate of how much this will set you back, there can be hidden costs of building a custom home.

From soil and contour tests to add-ons and design modifications, there’s more to building a house than meets the eye. That’s why it’s important to find a custom home builder you can trust, so you can stay informed and avoid unwanted surprises. To help you calculate the right budget for your build, here are the 10 most common hidden costs to keep in mind when building a custom home.

1. Soil Tests

Before construction begins, builders will carry out tests to check the quality of soil and the slope of your property. Naturally, poor soil makes building a custom home more challenging, which often means extra hands and extra hours. The same applies if the builders need to level a slope or adjust the plans accordingly.

2. Site costs

Largely based on the soil and contour tests, site costs can vary dramatically. Additional expenses can include cutting down trees, retaining walls, and connecting services such as water, electricity and gas.

3. Flooring

It might seem surprising, but flooring often isn’t included in the costs of building a custom home when you receive the quote. Whether you’re opting for carpet, tiles, cork or floorboards, make sure the flooring is included in your breakdown of costs before signing off on the estimate.

4. Driveways

Many custom home builders will only quote the costs of the dwelling. This means if you want a driveway, you will have to pay extra for it. Depending on the type and design of the driveway, this could range from quite cheap to very expensive.

5. Variations

When it comes to designing your dream custom home, you can’t always predict a change of heart. Just be aware that any modifications to the construction plan can be expensive, and can include legal costs, penalty clauses, extra labour costs, extra material costs, and engineering, drafting or approval costs. To avoid surprises, know exactly what your contract says in references to variations.

6. Land Registration

Make sure you chat to your custom home builder to see if the block of land you’re building on has been registered. If the land is new, there may be extra costs to consider, such as connecting electricity, plumbing and sewerage.

7. Bins

Buying new wheelie bins can set you back around $600. While it might not feel like a lot right now, when you’ve moved in and settled, it can come as quite a shock. Chat to your local council to find out the exact costs.

8. Natural Disasters

If you’re building your custom home in a bushy area, or close to a national park, then your property may have a Bushfire Attack (BAL) rating. This means changes will need to be made to the building to make sure it’s as bushfire safe as possible.

The same concept applies if you’re living in an area prone to flooding, as your house will need to be designed in a way that ensures people won’t die if a major flood comes through. These changes aren’t standard, so make sure to get an estimate of costs from your custom home builder.

9. Road Closures and Interruptions

If the builders need to close the road or interrupt traffic during the construction process, then you may incur fees for this. Make sure you talk this through with your custom home builder or get in touch with your local council or state government for an idea of how much this will cost.

10. Interest Repayments

When you’re building a custom home from scratch, you’ll likely take out a construction loan. On top of any temporary rental payments, you’ll also need to pay the interest on the price of the land and a deposit amount to the lender. While some lenders are ready to loan up to 95% of the total amount, just remember you would still need to pay for Lenders Mortgage Insurance too. Make sure you budget for this extra cash flow, which will vary depending on the size of your loan, fluctuating interest rates, and the scheduled payments to your builder.


At the end of the day, you can’t narrow down the cost of your custom home to an exact number. However, the more you’re aware of the potential hidden costs, the better you can manage your budget. Looking for expert and trusted advice? Chat to Mazzei Homes today.


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