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Renovating · Koste Knowledge Base

Can I Claim an Extension or Home Addition?

Published 26 June 2026 · Last updated 26 June 2026

Quick Answer

Yes, you can claim deductions on extensions or home additions, but primarily under **Division 43 of ITAA 1997** for capital works. These deductions apply to structural improvements and are usually spread over 40 years. Ensure your property is income-generating to qualify for these claims.

Adding an extension or making a home addition to your investment property can be a smart way to increase its value and rental income. However, claiming these costs as tax deductions involves understanding specific tax regulations. Primarily, deductions for extensions or home additions fall under Division 43 of the ITAA 1997, which covers capital works deductions.

Under Division 43, you can claim deductions for structural improvements such as extensions, renovations, or any alterations to the building. These deductions are usually claimed over 40 years, at a rate of 2.5% per annum, assuming the work was completed after 15 September 1987. It's crucial to note that the property must be income-generating for you to qualify for these tax benefits.

A common misconception is that you can claim the entire cost of an extension in a single tax year. Instead, these costs are capitalised and depreciated over the specified period. Investors often confuse capital works (Division 43) with plant and equipment deductions (Division 40), which cover removable or mechanical assets.

To see how this plays out, consider a practical example. Imagine you've added a new bedroom and bathroom to a 1995-built investment property in Richmond, Melbourne, at a cost of $100,000. Under Division 43, you can claim a deduction of $2,500 each year, which, at a 37% marginal tax rate, reduces your tax bill by $925 annually.

In our experience reviewing thousands of properties across Australia, we find that many investors overlook the potential deductions available for extensions. Often, they fail to maintain proper documentation of the construction costs, which can complicate claims. Additionally, some investors do not realise the importance of engaging a professional QS to ensure accurate cost allocation between capital works and plant and equipment.

The answer can differ depending on your situation. For example, if your property is a pre-1987 building, you might not be eligible for Division 43 deductions on some parts of the structure. Additionally, if you own the property through a Self-Managed Super Fund (SMSF), different tax implications might apply. Joint ownership can also affect how deductions are claimed, as each owner can only claim their share.

Getting professional advice is crucial when dealing with property tax deductions. Engaging a Chartered Quantity Surveyor ensures that your construction costs are accurately assessed and allocated, maximising your tax benefits. Likewise, consulting with an accountant familiar with property tax laws is essential to navigate any complexities specific to your situation.

Here are practical steps you can take immediately:

  • Confirm that your extension or addition qualifies as a capital work under Division 43.
  • Maintain detailed records of all construction costs and related expenses.
  • Engage a Chartered Quantity Surveyor to prepare a comprehensive depreciation schedule.
  • Consult with your accountant to understand how these deductions impact your overall tax strategy.
  • Review your property ownership structure to ensure optimal tax outcomes.
  • Plan future renovations with tax implications in mind.
  • Frequently Asked Questions

    Can I claim renovations done on a personal residence?

    No, renovations on a personal residence are not deductible under Division 43. The property must be income-generating to claim such deductions.

    How do I claim deductions for an extension on my tax return?

    You must report capital works deductions in your tax return under the 'Capital Works Deduction' section. Consult your accountant for accurate reporting.

    Are there state-specific rules for claiming extensions?

    While the federal rules under Division 43 apply nationally, certain state grants or incentives might affect your overall cost base. Check state-specific programs.

    Do I need a QS report for small renovations?

    Yes, even for small renovations, a QS report ensures accurate cost allocation and maximises your deduction potential.

    Is it better to renovate or extend for tax purposes?

    The decision should be based on potential rental income increase and personal financial goals. Tax benefits are similar under Division 43 for both options.

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    Written by Koste Team · Koste Chartered Quantity Surveyors · AIQS Member · RICS Member · TPB Registered · 1300 669 400 · info@koste.ai