Buy with family. Get on the Perth ladder sooner.
A first Perth house-and-land package is often blocked by one number: the deposit. A 20% deposit on an $845,000 home is $169,000. On a $929,000 home it is $186,000. Saving that, let alone while paying rent, can take years — years in which prices can move without you.
Co-ownership is attractive because it changes the maths. Two siblings, or a 23-year-old and her parents, put the deposit in together, combine income for the loan, and buy a new home that a tenant will rent. You get onto the Perth property market earlier. You add a dwelling to the supply. If the home qualifies as an eligible new build, the current negative gearing and CGT settings that still attach to new residential property can apply to the rented shares.
It is a way to buy sooner if the title, the loan and a written agreement are set up properly.
What co-ownership is
Co-ownership means two or more people buy one property together. Each person is on the title. Usually each person is also on the loan. You own a share of one house — not two houses, and not a handshake “you can stay when you visit.”
There are two common ways to hold the title in Australia.
Joint tenants is the structure most couples use. Owners hold the property together. If one dies, the survivor automatically owns the lot. That is simple for a couple. It is a poor default for siblings, or for a child buying with parents, because the dead owner’s share never reaches a will. Other brothers or sisters can be cut out.
Tenants in common means each person owns a named percentage — 50/50, 60/40, 70/30. That share can be left in a will, sold, or bought out. Contributions can be unequal and still match the title. For family investors who are not a couple, this is usually the safer structure. A solicitor should confirm it for your situation.
A new house-and-land package fits this strategy because the product is clear: one title, one builder, a home tenants will rent, and tax rules that still distinguish new supply from an established house bought after Budget night in May 2026.
Why people do it
- You buy years earlier. Two deposits beat one. Liam and Ella each find $84,500 instead of $169,000. Cassie and her parents each find about $93,000 instead of $186,000.
- Borrowing power is combined. A bank that will not write a loan on one young income may write it on two siblings, or on a child with parents.
- You get exposure to Perth prices while the house does a job — housing a family — instead of waiting on the sideline.
- Costs can be shared. Shortfall, rates and management split according to the agreement.
- New-build tax settings can still apply to a qualifying rental. From 1 July 2027, most established homes bought after 12 May 2026 will not let rental losses offset salary. Eligible new builds can. CGT on a later sale of a new dwelling held more than 12 months can still use the more favourable new-build rules, including the 50% discount where that election remains available. Shares of rent and deductions follow the ownership percentages.
- A child can travel and still own a base. Cassie rents the house while she is on the road. When she comes home she can move in if she chooses.
What can go wrong
- Family first becomes money first. Unpaid shortfall, a partner who wants out, or a disagreement about selling will strain the relationship. Without an agreement, that fight is also a legal bill.
- Each borrower is often liable for the whole loan, not “their half.” If one person stops paying, the bank can pursue the others for the full debt.
- The debt sits on everyone’s borrowing capacity. A joint loan can block the next purchase — a home of their own, or another investment — until the co-owned loan is refinanced or paid down.
- One person’s life event hits the others. Job loss, illness, relationship breakdown, or death all land on the title and the mortgage.
- Joint tenants can wreck a will. A parent who dies as a joint tenant with one child may leave nothing of that house to the other children.
- Living in the house changes the tax. Occupied shares are not a clean rental. That is why both case studies below keep the home tenanted unless someone later chooses to move in.
- Exit is slow if you did not plan it. Selling a half share on the open market is hard. A buyout clause and an independent valuation are what make an exit possible.
Co-ownership is a poor fit if anyone treats “we’re family” as a substitute for a deed, or if one person needs to live rent-free with no written occupancy rules.
Legal considerations and the co-ownership agreement
Do this work before you sign a land or building contract.
1. Decide the title. For siblings and for a child with parents, start with tenants in common and named percentages that match who put in the deposit. Change that only if a solicitor gives a reason.
2. Decide who is on the loan. Title and loan do not have to be identical, but lenders often want every owner on the mortgage — and they may treat each borrower as responsible for 100% of the debt.
3. Sign a co-ownership agreement. This is a deed drafted by a solicitor, not a template downloaded at midnight. It should cover at least:
- Each person’s percentage and how extra contributions (landscaping, rate rises, a cash call) are recorded
- Who pays the mortgage, insurance, rates and management, and what happens if one person misses a payment
- Whether anyone may live in the property, on what terms, and what rent they pay the others
- How rent is banked and split
- Decision rules — repairs, refinancing, selling
- A buyout process: independent valuation, first right to purchase, time to settle
- What happens on death, bankruptcy, or loss of capacity
- Dispute resolution before anyone files in court
- How the agreement is reviewed if someone wants to move in later (Cassie’s return)
4. Separate lawyers. Parents and child should not share one solicitor. Siblings can use one firm only if that firm is comfortable, and often they should not. Independent advice is part of the protection.
5. Update wills and insurance. Tenants in common means each share falls into the estate. Parents buying with one child need wills that deal with the other children. Hold buildings insurance and consider life cover that can pay out a share if someone dies.
6. Tax is not automatic. Rent and deductions follow the shares on title. Eligible new-build treatment depends on the dwelling and the legislation. If occupancy changes, see an accountant before the suitcases come home.
Getting this right can be the difference between building a portfolio and a family dispute.
Case study: Liam and Ella
Liam and Ella are brother and sister. Neither can put down a full deposit on a Perth house-and-land package without waiting years. Together they buy a new 4-bedroom, 2-bathroom home in Hilbert for $845,000, hold it as tenants in common 50/50, and rent it to a family. They are building a portfolio now, not waiting to do it one by one.
| Item | Amount |
|---|---|
| Package | $845,000 |
| Combined deposit (20%) | $169,000 ($84,500 each) |
| Loan | $676,000 |
| Rate | 6.04% interest-only, 30 years |
| Interest | $785 a week ($40,830 a year) |
| Rent | $680 a week ($35,360 a year) |
| Shortfall | $105 a week ($5,470 a year) |
| Each sibling’s share of the shortfall | $53 a week |
Other costs (such as rates, insurance, management) are left out.
On rent versus interest alone they are in by $105 a week — $53 each. That is the price of starting together instead of saving another five years apart.
Because nobody lives there, the whole house is an investment. If it qualifies as an eligible new build, rental losses can still offset other income from 1 July 2027, and CGT on a later sale can still use the new-build rules if they hold more than 12 months. Deductions follow the 50/50 shares.
Interest-only is usually a limited term. Both names are typically on the hook for the full $676,000. Their agreement gives each sibling first right to buy the other out at an independent valuation if one wants to exit.
After five years
The loan is still $676,000 if they stay interest-only and do not pay down principal.
| Growth assumption | Value after 5 years | Combined equity | Each sibling’s equity |
|---|---|---|---|
| 8% per year | $1,242,000 | $566,000 | $283,000 |
Figures rounded.
At 8% a year each sibling’s $84,500 deposit has become about $283,000 of equity. That rate is a planning scenario, not a Hilbert forecast.
Case study: Cassie and her parents
Cassie is 23. She goes halves with her parents on a new 5-bedroom, 3-bathroom house-and-land package for $928,900. They hold it as tenants in common 50/50.
They rent it from the start. Cassie then travels around Australia for as long as she wants. The house stays an investment for all three of them. When she comes home she can move in if she chooses — she already owns half of a place to come back to.
| Item | Amount |
|---|---|
| Package | $928,900 |
| Combined deposit (20%) | $185,780 ($92,890 Cassie / $92,890 parents) |
| Loan | $743,120 |
| Rate | 6.04% interest-only, 30 years |
| Interest | $863 a week ($44,884 a year) |
| Rent | $810 a week ($42,120 a year) |
| Shortfall | $53 a week ($2,764 a year) |
| Cassie’s share of the shortfall | $27 a week |
Other costs (such as rates, insurance, management) are left out.
On rent versus interest the gap is small — about $53 a week all up, $27 for Cassie. That is before rates and management. Because the house is rented while she travels, it can be treated as an investment for everyone, including her half. Eligible new-build negative gearing and CGT settings can still apply to those shares. If she later moves back in, her half may stop being an investment and the tax splits. Plan that change with an accountant before she unpacks.
Parents should update their wills so Cassie’s siblings are not cut out. The agreement should say who covers Cassie’s $27 if she is on the road and cash is tight, and how that is squared up when she returns. First right to buy out if anyone wants to sell.
After five years
Interest-only, loan still $743,120.
| Growth assumption | Value after 5 years | Combined equity | Cassie’s 50% | Parents’ 50% |
|---|---|---|---|---|
| 8% per year | $1,365,000 | $622,000 | $311,000 | $311,000 |
Figures rounded.
At 8% a year Cassie’s $92,890 deposit has become about $311,000 of equity — and she still has a 5-bed home she can move into. That rate is a planning scenario, not a forecast. If the loan was principal plus interest then Cassie would pay about $111 per week, but end up with $26,000 more equity as she has reduced the loan.
General information only. Not tax, legal or financial advice. Growth figures are illustrations, not predictions. Co-ownership, loans and CGT depend on the contract, the title and current law. Get a solicitor to draft the agreement and a registered tax agent to confirm the new-build treatment before you sign.