Buying with a friend, sibling or parent pools incomes and down payments, but unlike a couple, co-owners who aren’t partners have no family-law framework to fall back on if things go wrong. Everything rests on how the title is held, who is on the mortgage and what the co-owners agree in writing. This guide covers buying with people who aren’t your spouse or partner: the title structure, qualifying together, the co-ownership agreement, splitting unequal contributions, tax and the ways out. It is one of our guides to buying outside the standard single-borrower route.
Couples buying together are covered in joint mortgages for spouses and partners, and a parent who wants to back a child’s mortgage without owning part of the home is usually a co-signer or guarantor rather than a co-owner, explained in co-signing or guaranteeing a mortgage.
How the title is held
Joint tenants hold equal shares, and a deceased owner’s share passes automatically to the survivors; tenants in common can hold unequal shares (60/40, 70/30) that pass under each owner’s will. Because contributions between friends or relatives are often unequal and each owner usually wants their share to go to their own heirs, co-owners who aren’t partners commonly hold title as tenants in common; the full comparison is in joint tenancy vs tenancy in common.
With tenants in common, the agreed percentages are registered on title, so the agreement and the title say the same thing.
Qualifying for the mortgage together
| Factor | How lenders assess co-buyers |
|---|---|
| Income | The gross income of every applicant, combined |
| Debts | Every applicant’s debt payments, combined |
| Credit | Each applicant’s credit is reviewed; one weak file can affect the rate or the approval |
| Down payment | Can come from any combination of the applicants |
| Liability | Joint and several: each borrower is liable for the full mortgage, not just their share |
Lenders apply the mortgage stress test to the combined application, and the combined payments must fit within the debt service limits: For an insured mortgage, CMHC caps your housing costs at 39% of gross income (GDS) and your housing costs plus other debt payments at 44% (TDS); lenders set their own limits for uninsured mortgages.
- Joint and several liability. If one co-owner stops paying, the lender can pursue any of the others for the whole remaining balance, whatever the co-ownership agreement says.
- The weakest file matters. One co-owner with poor credit or high debts can reduce the amount the group qualifies for or raise the rate.
- Number of borrowers. Lenders limit how many people can be on one mortgage, and the limit varies by lender.
- First-time buyer status. Each co-owner’s status is assessed separately for programs such as the FHSA and the Home Buyers’ Plan, so one buyer may be able to use them while another can’t.
Siblings, friends or parent and child
Siblings
| Advantages | Drawbacks |
|---|---|
| Family trust and familiarity | Family disputes can be more emotionally charged |
| Parents may help with the down payment | Different life stages: one may marry or relocate |
| Long-term goals are often aligned | Inheritance questions if a parent helps one sibling more |
Friends
| Advantages | Drawbacks |
|---|---|
| Costs and equity are shared | Life changes (a partner, children, a job move) arrive at different times |
| You choose a compatible person to live with | The friendship is at risk if a dispute arises |
| Pooled money can buy a better location | Different financial habits and priorities |
Parent and adult child
| Advantages | Drawbacks |
|---|---|
| The parent helps the child into the market | The mortgage counts against the parent’s own debt ratios |
| Can be structured as co-ownership, a loan or a gift | A parent’s share of a home they don’t live in can be taxable on sale |
| Keeps the family close | May complicate other siblings’ inheritance |
The co-ownership agreement
A co-ownership agreement is the most important document in the arrangement. Co-owners usually have a real estate lawyer draft it before they make an offer, with each person getting their own legal review.
| Topic | What to define |
|---|---|
| Ownership percentages | Each person’s share, usually tied to what they contributed |
| Paying the costs | Who pays the down payment, mortgage, property tax, insurance, utilities, maintenance and repairs, and in what proportions |
| Decisions | Which decisions need everyone’s consent (renovations, refinancing, spending above a set amount) |
| A shared account | Whether a joint account holds monthly contributions for shared costs |
| Right of first refusal | If one owner wants to sell, the others get the first chance to buy that share |
| Buyout price | How the home is valued for a buyout, such as one independent appraisal or the average of two |
| Sale triggers | Events that force a sale or buyout: death, bankruptcy, a new relationship, a move for work, a co-owner who can’t pay |
| Default | What happens if one owner stops paying their share, including a cure period |
| Occupancy | Who lives there, whether a partner can move in, and how that changes the costs |
| Dispute resolution | Mediation or arbitration before court, and who pays for it |
| Death or incapacity | What happens to a co-owner’s share, and any life insurance that funds a buyout |
| Exit timeline | How much notice an owner gives before leaving, and how long a buyout or sale can take |
Splitting unequal contributions
| Scenario | How co-owners often structure it |
|---|---|
| Equal down payment, equal income | 50/50 ownership, with costs split equally |
| Unequal down payment | Ownership in proportion to the down payment, or equal ownership with a promissory note for the difference |
| Equal down payment, unequal income | Costs split by income, or equal ownership with a side agreement on payments |
| One owner does most of the renovation work | An agreed dollar value for the work, credited to that owner’s share |
Two co-buyers put down $80,000 and $20,000 and agree to split the mortgage payments equally. They agree on ownership of 65% and 35%, which gives the larger down payment more weight without ignoring the equal payments. Any split can work, as long as it is written into the co-ownership agreement and registered on title.
Tax on a co-owned home
| Tax issue | How it works for co-owners |
|---|---|
| Principal residence | Each co-owner who lives in the home can generally shelter their own share from tax on a sale; an owner who doesn’t live there can’t. The rules are in the principal residence exemption |
| Capital gains on sale | Each owner reports their share of any gain not sheltered; 50% of a capital gain is included in income |
| Rent between owners | If one owner moves out and the other pays them rent, that rent can be taxable income |
| Land transfer tax | Land transfer tax is charged on the whole purchase; where a first-time buyer rebate exists, a co-owner who doesn’t qualify can reduce it |
What can go wrong
| Risk | How the agreement handles it |
|---|---|
| One owner stops paying | A default clause with a cure period and a buyout option, plus a reserve fund for shortfalls |
| One owner wants to sell, another doesn’t | The right of first refusal, with a set timeline and valuation method |
| Disagreement over renovations or repairs | A spending threshold above which every owner must agree in writing |
| One owner moves a partner in | A clause on additional occupants and how they affect the costs |
| One owner’s credit deteriorates | No effect on the existing mortgage, but it can block a future refinance or renewal elsewhere |
| One owner loses their job | A temporary payment adjustment with a catch-up schedule |
| A co-owner dies | Life insurance and the agreement fund a buyout from the estate |
| A creditor of one owner registers a claim on the home | Few protections exist, which is a risk of co-ownership itself |
| The relationship breaks down | Mediation first, then the agreed buyout or sale |
Ways out
A buyout
The remaining co-owners buy the departing owner’s share:
- The home is valued by the method in the agreement.
- The departing owner’s equity is their share of the value minus their share of the mortgage balance.
- The remaining owners refinance the mortgage in their names only.
- The departing owner is paid their equity and taken off the title.
The remaining owners must qualify for the whole mortgage without the departing owner’s income. If they can’t, the home may have to be sold.
A sale
If no one buys the others out, the home is sold, and the proceeds are split by ownership share after paying off the mortgage, the closing and selling costs and any shared expenses still owing.
Alternatives to co-owning
| Option | How it works | Trade-off |
|---|---|---|
| One buys, the other rents | One person owns and the other is a tenant | Simpler, but only the owner builds equity |
| A gifted down payment | A parent gives the down payment and the child owns alone | No shared liability, but the parent has no stake |
| A co-signer or guarantor | A parent backs the mortgage without living there | The parent carries the liability without owning a share |
| A shared equity mortgage | A program or lender takes a share of the home’s value in return for part of the down payment | A smaller mortgage, but part of the gain goes to the partner |
The bottom line
Co-owning with friends or family works when it is run like a business arrangement: title held to match each person’s share, every borrower aware that they are liable for the whole mortgage, and a written co-ownership agreement that settles costs, decisions and exits before anyone moves in.
Sources
The figures and rules on this page come from these sources, last checked against them between September 23, 2026 and September 29, 2026. How we check facts.
- Canada Revenue Agency: Capital Gains – 2025
- CMHC: Calculating GDS / TDS
- CMHC: CMHC Purchase