Co-Purchase Guide

Buying a Multiplex With Your Family

A new duplex in Vancouver costs $1.3M–$1.9M. A fourplex runs $2.5M–$3M. For most families, the only practical path is pooling resources with another household — combining incomes to qualify, splitting the down payment, and living in separate units under one roof. Here is exactly how that works in BC.

MultiLiving Editorial|Updated July 2026

4 peopleMax co-borrowers on a joint mortgage at most major lenders

$1,500–$3,000Cost of a co-ownership agreement with a BC real estate lawyer

50–80%Of projected rental income that lenders count toward qualification

What You'll Learn

Key Topics

Two Incomes, One Mortgage

Combining two household incomes can more than double your borrowing power. A household earning $120K qualifies for roughly $550K on its own. Two households earning $120K each can qualify for $1.2M — enough for a duplex in Vancouver when neither family could get there alone.

Separate Units, Not a Shared Home

Each family lives in their own unit with a private entrance, kitchen, and living space. You are close enough to share the yard or watch each other's kids, but you are not sharing a bathroom or a front door. This is what makes the co-purchase work long-term.

The Down Payment Gets Easier

Reaching 20% down on a $1.5M purchase means saving $300,000 — almost impossible for one household. When two households each contribute, that target becomes realistic. Co-purchasing is often the only path to avoiding CMHC mortgage insurance on a larger property.

The Co-Ownership Agreement Protects Everyone

A written co-ownership agreement — a private legal contract between you and your co-buyers — covers ownership percentages, how costs are split, how decisions are made, and what happens if someone wants out. It costs $1,500–$3,000 with a BC lawyer. Without one, a disagreement becomes litigation.

Tenants in Common Is the Flexible Choice

Tenants in common lets each party own a defined percentage of the property (60/40, 50/50, or any split). You can each leave your share to whoever you choose in your will. This is more common for family co-purchases than joint tenancy, which forces equal shares and restricts estate planning.

Plan the Exit Before You Buy

The question most families avoid is: what if one of us wants to sell in five years? Your co-ownership agreement should include a right of first refusal — the other family gets to buy your share before you list it publicly — and a clear buyout process so no one is stuck.

The Case for Co-Purchase

Why Families Buy Multiplexes Together

Two families buy a multiplex together to combine incomes for mortgage qualification, split a larger down payment, and live in separate units at prices neither household could reach alone. The benchmark price for a new duplex in Vancouver is $1.3M–$1.9M; a fourplex runs $2.5M–$3M.

Mortgage qualification

Lenders look at total household income when deciding how much they will lend. Two families on one application means two incomes count. A household earning $120,000 per year qualifies for roughly $550,000 on its own. Two households at the same income qualify for closer to $1.2 million. That difference is the entire gap between what one family can afford alone and what a duplex actually costs in Vancouver today.

Down payment pooling

To avoid mortgage default insurance (called CMHC insurance), you need at least 20% down. On a $1.5 million property, that is $300,000. Two households each saving $150,000 get there twice as fast — and once you clear 20%, you avoid the CMHC insurance premium, which can add $30,000–$50,000 to your total mortgage cost.

Lifestyle

A multiplex is not a shared home. Each family gets their own front door, their own kitchen, their own space. In a duplex, the two units are typically side by side or stacked. In a fourplex, each family may be on their own floor. You are neighbours, not roommates. That distinction is what makes co-purchasing a multiplex work for families who would never consider sharing a single house.

BC market context

The benchmark price for a newly built duplex in Vancouver sits between $1.3M and $1.9M depending on neighbourhood, size, and finishes. A new fourplex typically runs $2.5M to $3M for the whole building. These prices reflect land values in established Metro Vancouver neighbourhoods. For most households, co-purchasing is not a compromise — it is the only way to access this type of property.

Legal Ownership

Two Ways to Hold the Title

When two families buy a property together, they have to decide how ownership is recorded on the title. BC law offers two main options. The choice affects your estate planning, your flexibility, and what happens if one party wants out.

Joint Tenancy

Simpler, less flexible

Both parties own the whole property together, equally. If one owner dies, their share passes automatically to the surviving owners — this is called the right of survivorship. You cannot hold unequal shares (it must be 50/50 for two parties). You also cannot will your share to a child or anyone outside the ownership group; it goes to your co-owners by operation of law.

Best for: spouses buying together, or parties who want the simplest possible structure.

Tenants in Common

More common for family co-purchase

Each party owns a defined percentage share. You can split it 50/50, 60/40, 70/30 — whatever reflects each family's contribution. Each owner can will their share to whoever they choose. If one party contributed a larger down payment, you can record that as a larger ownership percentage. There is no automatic survivorship — your share goes where your will directs it.

Best for: two unrelated families, or any co-purchase where contributions are unequal or estate flexibility matters.

A note on stratified multiplexes

Many new multiplexes in Metro Vancouver are stratified — meaning each unit is registered as a separate legal title under the Strata Property Act. Once a building is stratified, each family owns their unit outright and holds their own mortgage, exactly like a condo. Strata is the cleanest structure for co-purchasing families because it gives each household full independence: you can sell your unit without the other family's consent, and your mortgage is entirely separate.

The catch: during the pre-sale period and construction phase, strata registration has not happened yet. Until the building is built and registered, co-buyers typically purchase as tenants in common or joint tenants on a single title. Your co-ownership agreement governs the relationship until strata titles are issued.

Source: BC Strata Property Act (SBC 1998, c. 43). Strata registration timing varies by municipality and developer.

Financing

Mortgage Options for Co-Purchasers

Most major lenders in Canada allow co-purchase mortgages. The rules are straightforward — but there are a few details that surprise buyers, especially around rental income and debt.

Up to four co-borrowers

Most major Canadian banks and credit unions allow up to four people on a single mortgage application. That means two families — each with two income earners — can potentially all appear on the same mortgage. All co-borrowers' incomes count toward qualification. The trade-off: all co-borrowers' debts count too. If one party is carrying significant student loans, a car loan, or another mortgage, those obligations reduce the total amount you can borrow together. Get each party pre-approved individually first, so you can see the full picture before combining.

Rental income from the units you do not live in

If you are buying a fourplex and each family occupies one unit, the other two units can be rented out. Lenders typically allow 50–80% of projected rental income from those units to count toward your qualification. On two units renting at $2,200 per month each, that adds $2,200–$3,520 per month to your qualifying income. This can make a meaningful difference in how much the bank will lend. Projected rental income must be supported by a market rent appraisal or comparable listings in the area.

Vancity Mixer Mortgage

Vancity Credit Union offers a mortgage product specifically designed for co-ownership purchases. It allows flexible repayment structures and explicitly accounts for the fact that co-owners may have separate financial situations, different income levels, and different repayment timelines. If you are buying with a family member who has a different financial profile than you — different income, different debt load, different repayment goals — this product is worth exploring.

CMHC mortgage insurance still applies

CMHC (Canada Mortgage and Housing Corporation) mortgage insurance is available for co-purchase transactions, as long as at least one buyer intends to occupy the property as their primary residence. The property must have no more than four units. Insurance premiums range from 2.80% to 4.00% of the insured amount depending on how much you put down. If both families together reach 20% down, you avoid the insurance premium entirely — one of the key financial benefits of pooling down payments.

Before you combine: get pre-approved separately first. Each party should go through the full mortgage pre-approval process on their own before combining finances. This shows you exactly where each party stands — income, debts, credit score — and surfaces any issues before you have committed to buying together. A mortgage broker experienced with co-purchase transactions is worth the time.

Sources: CMHC mortgage loan insurance premium schedule (cmhc-schl.gc.ca). Ratehub.ca co-borrower mortgage guide (2026). Vancity Mixer Mortgage product details (vancity.com). Major lender co-borrower policies (TD, RBC, Scotiabank, BMO — verified 2026).

Legal Protection

The Co-Ownership Agreement: Why You Need One

A co-ownership agreement is a private legal document between co-buyers. It is entirely separate from the mortgage and the title. Think of it as the rulebook for your co-purchase — written down before anyone gets emotional about it.

“Buying a house with family is a business partnership. The co-ownership agreement is your partnership contract. Getting it right takes a few thousand dollars and a few hours — not getting it takes months and tens of thousands in legal fees.”

What the agreement must cover

Ownership percentages (e.g., 60/40 or 50/50)
How monthly costs are split: mortgage payments, strata fees, property taxes, maintenance, and capital repairs
How decisions are made: one vote each, or proportional to ownership share
What happens if one party wants to sell (timeline, right of first refusal, valuation method)
What happens if one party stops paying their share
How disputes are resolved (mediation before litigation)

Cost and process

A co-ownership agreement drafted by a BC real estate lawyer typically costs $1,500–$3,000 for a straightforward two-family purchase. Complexity (more parties, unequal contributions, business interests) pushes the cost higher.

Each party should review the agreement with their own independent legal counsel — not the same lawyer. You are on opposite sides of the same contract. What protects one party may be less favourable for the other.

The agreement does not need to be filed with a government office. It is a private contract enforceable in BC courts. Keep signed originals with each party and with both lawyers.

Without a co-ownership agreement, if one party stops paying or announces they want to sell, the only remedy is a court application — which typically costs $20,000–$50,000 in legal fees and takes 12–24 months.

Sources: BCREA Legally Speaking (co-ownership guide). Law Society of BC practice tips on co-ownership. Stewart Title co-purchase risk advisory.

Taxes and Rebates

PTT and GST: What Changes in a Co-Purchase

Tax and rebate eligibility is assessed per buyer in a co-purchase, not for the property as a whole. This matters most when one party has bought before and the other has not.

Tax or Rebate	How it works in a co-purchase	Example
Property Transfer Tax (PTT)	Each co-buyer pays PTT on their ownership percentage of the purchase price. Exemptions are assessed individually.	On a $1.6M duplex split 50/50: each party pays PTT on $800K.
First-time buyer PTT exemption	If you are a first-time buyer but your co-purchaser is not, only your share of the price qualifies for the exemption. The other buyer pays full PTT on their share.	Family A (first-time buyers) pays $0 PTT on their 50% share if it is under $835K. Family B (previous owners) pays full PTT on their 50% share.
GST New Housing Rebate	All buyers on the purchase contract must qualify as first-time buyers (or owner-occupiers) for the full rebate to apply. If one buyer does not qualify, the rebate is reduced proportionally.	Two families buying a new $1.5M duplex: if both families plan to occupy their unit, both may qualify. If one family is buying as an investment, the rebate is affected for their share.
Newly built home PTT exemption	Available to any buyer who moves into a new home within 92 days and lives there for 12+ months. Each co-buyer's eligibility on their share is assessed separately.	Both families moving in = both potentially qualify on their respective shares, up to the $1.1M threshold per party.

For a full breakdown of every BC buyer savings program — including first-time buyer exemptions, the newly built home PTT exemption, and all GST rebate rules — see the Tax Rebates for Multiplex Buyers in BC guide.

Sources: BC Gov Property Transfer Tax rates and exemptions (gov.bc.ca, 2026). Canada Revenue Agency GST/HST New Housing Rebate (CRA, 2026). Bill C-4 GST exemption on new purpose-built rental housing.

Exit Planning

What Happens If One Family Wants to Sell?

Life changes. Jobs relocate. Families grow or downsize. The exit scenario is the one most co-buyers avoid planning for — and the one that causes the most conflict if they do not.

Stratified multiplex: unit titles are separate

If the building has been stratified — each unit registered as its own legal title — then each family owns their unit independently. One family can list their unit for sale without needing the other family's approval. Your mortgage is separate. Your title is separate. The sale proceeds are yours.

Your co-ownership agreement should still specify a right of first refusal: before listing on the open market, the selling family offers the other family the chance to purchase at the same price and terms. This keeps the property in family hands if the other party wants to consolidate ownership.

Non-stratified: one title, shared ownership

If you hold the property as tenants in common on a single title, selling requires more coordination. One family cannot sell their ownership interest on the open market easily — most buyers do not want to purchase a 40–50% undivided interest in a property with strangers.

In practice, the exit options are: the remaining family buys out the departing family's equity, or both families agree to sell the entire property. Your co-ownership agreement should specify a buyout process and timeline (90–180 days is typical), a valuation method (independent appraisal by a BC-certified appraiser), and what happens if the parties disagree on price.

Right of first refusal: the single most important exit clause

A right of first refusal means: before the selling family can list their unit or share on the open market, they must first offer it to the other family at the same price and on the same terms. The other family typically has 30–60 days to decide. If they decline, the seller is free to list publicly.

Without this clause, your neighbour in the other unit could theoretically sell to a stranger — someone you have never met, with no shared history or expectations. That is an uncomfortable situation that most families want to avoid. A right of first refusal prevents it.

The bottom line

Co-purchasing a multiplex with family is one of the most financially sensible moves available to households who cannot reach Vancouver or Burnaby prices on a single income. Two households combining their incomes, down payments, and shared costs can access a property — and a neighbourhood — that neither could afford alone.

The legal side is manageable but not optional. Choosing between tenants in common and joint tenancy affects your estate flexibility and your exit options. The co-ownership agreement — $1,500–$3,000 with a BC real estate lawyer — is not a nice-to-have. It is the document that turns a handshake arrangement into a durable legal structure. Families who skip it regret it when circumstances change.

The tax picture rewards those who plan. PTT exemptions are assessed per buyer, not per property. If one family is buying for the first time and the other has owned before, structuring ownership percentages thoughtfully can significantly reduce the combined tax bill. A good lawyer and a tax accountant who knows real estate are worth consulting before you sign anything.

Plan the exit before you need it. A right of first refusal and a written buyout process cost nothing extra to add to your co-ownership agreement, and they prevent the most common source of conflict between families who buy together.

Ready to explore this path? Read the Multi-Generational Living guide for the lifestyle side, review Financing Your Multiplex for the full mortgage picture, or talk to our team and we will help you find the right property for your family's situation.

Data: CMHC mortgage rules and co-borrower guidelines (cmhc-schl.gc.ca). BC Gov PTT exemptions (gov.bc.ca). BCREA co-ownership guidance. Ratehub.ca mortgage qualification estimates (2026). Strata Property Act SBC 1998, c. 43.

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Summary

Key Takeaways

Two household incomes on one mortgage can more than double your buying power — a key reason families co-purchase.
Tenants in common is more flexible than joint tenancy: each party owns a defined share and can will it independently.
A co-ownership agreement costs $1,500–$3,000 with a BC lawyer and is non-negotiable when families buy together.
Each co-buyer pays PTT on their ownership share only — first-time buyer exemptions are assessed individually.
Lenders count 50–80% of projected rental income from units you do not occupy toward your qualification.
For stratified multiplexes, each family eventually holds a separate title and can sell their unit without the other's consent.

Common Questions

Frequently Asked Questions

Can two families buy a multiplex together in BC?

Yes. Two or more families can purchase a multiplex together as co-owners. The most common structures are tenants in common (each party owns a defined share) and joint tenancy (equal shares with right of survivorship). For new multiplexes that are stratified — meaning each unit gets its own title — each family can eventually own their unit independently.

How many people can be on a joint mortgage in BC?

Most major Canadian lenders allow up to four people on a single mortgage application. All co-borrowers' incomes count toward qualification, which is the main advantage of pooling resources. All co-borrowers' debts also count, so each person's financial picture matters.

What is a co-ownership agreement and do I need one?

A co-ownership agreement is a private contract between co-purchasers that covers ownership percentages, how costs are divided, how decisions are made, and what happens if one party wants to sell or stops paying. You need one. Without it, a dispute between co-owners can only be resolved through expensive litigation.

How does PTT work when two families buy together?

Each co-buyer pays BC Property Transfer Tax on their percentage of the purchase price. If you own 50% of a $2M property, you pay PTT on $1M. If you are a first-time buyer but your co-purchaser is not, only your share qualifies for the first-time buyer exemption.

What happens when one family wants to sell their share?

For a stratified multiplex with separate unit titles, each family can sell their unit independently without affecting the others. For a non-stratified co-purchase on a single title, selling requires either a buyout by the remaining owners or a sale of the whole property. Your co-ownership agreement should spell out the process and timeline in advance.

What is the Vancity Mixer Mortgage?

The Vancity Mixer Mortgage is a BC-specific mortgage product designed for co-ownership purchases. It allows flexible repayment structures and explicitly accounts for the separate finances of co-owners — useful when two households have different income levels or want different repayment schedules.

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