In short
These are Quebec rules. In divided co-ownership (a “condo”), you own your private portion and a share of the common portions, managed by a syndicate. In undivided co-ownership, you own a share of the whole building, with no private portion. The Civil Code presumes equal shares and lets each co-owner mortgage their share, but the Chambre des notaires notes that lenders tend to be reluctant to lend without the involvement of all the co-owners. An indivision agreement, published in the land register, sets out use, expenses and how to exit. A notary prepares it.
What you really own
| Divided (condo) | Undivided | |
|---|---|---|
| Your right | A private portion, physically divided, and a share of the common portions | A share of the whole building, with no physical division |
| The governing document | The declaration of co-ownership, published; the co-owners form a syndicate | The indivision agreement, if you sign one; once published, it can be set up against third parties |
| Your shares | Set by the declaration | Presumed equal, even if down payments are unequal |
| Mortgaging | Your fraction | Your share, but lenders tend to be reluctant without all the co-owners |
| Selling your share | Under the declaration of co-ownership | The others can turn the buyer away (60 days, one year at most); an agreement often includes a right of first refusal |
| Repossessing a unit | — | Not possible, unless there is only one other owner and that person is your spouse |
Sources: Civil Code of Québec, arts. 1010, 1013 to 1016, 1022, 1038, 1039, 1052 and 1958; Chambre des notaires du Québec; Éducaloi (legal information non-profit).
Why so many Montreal plexes sell as undivided co-ownership
A building that has, or has had in the past 10 years, at least one dwelling cannot be converted into divided co-ownership without authorization from the Tribunal administratif du logement. In the Montreal agglomeration, that conversion is prohibited, unless an exemption is granted by resolution of the municipal council. The ban does not cover a building whose dwellings are all occupied by undivided owners.
The Civil Code also provides an exit: three-quarters of the undivided co-owners, holding 90% of the shares, can end the undivided co-ownership of a mainly residential building to establish divided co-ownership (art. 1031), subject to the conversion rules.
Financing
The Civil Code allows each undivided co-owner to alienate or mortgage their share. The Chambre des notaires specifies that in case of default, the other co-owners are not held liable, but that creditors tend to be reluctant to lend to one co-owner without the involvement of the others.
No official source sets a minimum down payment for an undivided share: it depends on the lender. Before making an offer, ask a mortgage broker which lenders finance undivided co-ownership in your area, and on what terms. If the building is a plex, the plex financing guide gives CMHC’s rules for the whole building.
The indivision agreement
According to the Chambre des notaires, the agreement can cover its duration, use of the premises, maintenance and renovations, sharing of expenses, ownership of improvements, restrictions on selling, management of the building and how the property is divided when the indivision ends. It usually includes a right of first refusal: anyone who wants to sell must first offer their share to the others. It is renewed every 30 years and must be published in the land register to be enforceable against third parties.
Before buying an undivided share
- Read the existing indivision agreement, and check with a notary that it is published in the land register.
- Check the right of first refusal: can the other co-owners buy the share before you?
- Have a mortgage broker confirm that a lender will finance your share, and on what terms.
- If you are targeting a unit occupied by a tenant, note that the owner of an undivided share cannot repossess it, except in the spouse case set out in article 1958.
- Have a notary prepare the deed of purchase and, if needed, a new agreement.
Frequently asked questions
What is the difference between divided and undivided co-ownership?
In divided co-ownership, each co-owner owns a private portion and a share of the common portions. In undivided co-ownership, each owns a share of the whole building, with no private portion.
How long does an indivision agreement last?
30 years at most, renewable. A longer agreement is reduced to 30 years.
Can an undivided co-owner repossess a unit?
No, unless there is only one other owner and that person is your spouse (Civil Code, art. 1958).
Are the shares equal if our down payments differ?
The law presumes them equal, even if down payments and payments are unequal. For a different split, it must be written in the deed of sale or the indivision agreement.
Sources
- Code civil du Québec, art. 1010 à 1031, 1038, 1039, 1052, 1958 (LégisQuébec) read 2026-10-08
- Loi sur le Tribunal administratif du logement, art. 51 (LégisQuébec) read 2026-10-08
- Chambre des notaires — Que comprend la convention d'indivision ? read 2026-10-08
- Chambre des notaires — What rights do undivided co-owners have? read 2026-10-08
- Éducaloi (organisme d'information juridique) — Quel type d'habitation acheter au Québec ? read 2026-10-08
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Updated
General information, not legal or financial advice. For your situation, consult a notary or a mortgage broker.