ImmoMulti — direct buyer of income properties on the North Shore — regularly sees owners underestimate what sets the sale of a mixed-use building (housing + commercial unit) apart from that of a purely residential plex. Three differences carry real weight: the commercial portion is subject to GST and QST on sale, while used residential is generally exempt; commercial leases follow rules distinct from those of a residential lease and must be transferred carefully; and the valuation must capitalize two income streams with different risk profiles. Add a narrower buyer pool, and you understand why a mixed-use building rarely sells "like a plex."
How does selling a mixed-use building differ from selling a pure plex?
A purely residential used plex is generally GST/QST exempt, its leases are framed residential leases, and its buyers are numerous. A mixed-use building adds a taxable commercial portion, freely negotiated commercial leases, and a two-use valuation — hence a more complex process and a smaller buyer pool.
Structurally, a mixed-use building resembles a plex: several dwellings, one building, rental income. But the moment a commercial unit is added at street level — a convenience store, a salon, an office, a café — the building shifts into a hybrid tax and legal regime. The seller must deal simultaneously with housing rules and commercial rules.
This duality affects everything: the transaction's taxation, the nature of the leases, the valuation method, and even the type of financing the buyer can obtain. An owner who approaches the sale as if selling a simple triplex on the North Shore risks costly surprises at the notary's table.
Why is the commercial portion subject to GST/QST?
According to Revenu Québec, the sale of a used residential property (not new, no major renovations) is generally GST/QST exempt. The commercial portion is not exempt: its sale is taxable. The price of a mixed-use building must therefore be allocated between the residential part (exempt) and the commercial part (GST 5% + QST 9.975%).
This is the most misunderstood difference. Revenu Québec specifies that the sale of a residential housing property that is not new and has not undergone major renovations is generally exempt from tax. That is why a used plex usually sells without GST/QST.
The commercial part of a mixed-use building does not benefit from this exemption: its supply is taxable. The sale price must therefore be allocated between the value attributable to residential (exempt) and the value attributable to commercial (taxable at 14.975%: GST of 5% and QST of 9.975%).
Good news for structuring the transaction: when the buyer is registered for GST/QST and intends to use the building primarily (more than 50%) in their commercial activities, Revenu Québec indicates that the buyer must remit the GST and QST themselves (self-assessment), no later than the filing date of their return for the period concerned. The seller then does not have to collect tax on the commercial portion.
| Portion of the mixed-use building | GST/QST treatment on sale | Source |
|---|---|---|
| Dwellings (used residential, not majorly renovated) | Generally exempt | Revenu Québec — Sale of residential properties |
| Commercial unit | Taxable (5% GST + 9.975% QST = 14.975%) | Revenu Québec — Taxable vs exempt supplies |
| Registered buyer, commercial use > 50% | Self-assessment by the buyer | Revenu Québec — Purchase/sale of a property |
Sources: Revenu Québec — Sale of residential properties; Revenu Québec — Purchase, sale of a property. GST (5%) and QST (9.975%) rates are the rates in effect. Validate the allocation with a tax advisor or notary.
Watch the price allocation
A poorly documented allocation between residential and commercial portions can trigger a tax reassessment. Have the split established by a professional before signing the deed of sale, and state it clearly in the offer to purchase.
How do you transfer commercial leases to the buyer?
Unlike a residential lease, a commercial lease does not renew automatically: according to Éducaloi, the commercial tenant must normally leave at the end of the lease, unless agreed otherwise. On the sale, the buyer takes the seller's place. A published fixed-term commercial lease with more than 12 months remaining generally cannot be terminated by the new owner.
The commercial lease is very different terrain from housing. Éducaloi notes that a commercial lease can prohibit the tenant from assigning the lease or subletting, and that it does not renew automatically like a residential lease: the commercial tenant must normally vacate at the end of the lease, unless otherwise agreed.
For the seller of a mixed-use building, this has direct consequences. A commercial unit whose lease is nearing its end represents a vacancy risk for the buyer, who will factor it into their price. Conversely, a solid commercial lease, with a comfortable remaining term and a reliable tenant, becomes a selling point.
On the tenant-protection side, Éducaloi indicates that a commercial tenant can publish their lease in the land registry to protect it against a buyer: a published fixed-term lease with more than 12 months remaining generally cannot be terminated by the new owner. The buyer will therefore review the land registry entries as part of their due diligence.
- Remaining term: a long, published commercial lease reassures the buyer (predictable income);
- Assignment clauses: check whether your leases allow or prohibit assignment and subletting;
- Land registry publication: know which leases are published, as it shapes the new owner's rights;
- Use compliance: ensure the commercial use complies with municipal zoning.
How do you value a mixed-use building by capitalizing two uses?
Like any income property: you establish net operating income, then apply an overall capitalization rate (TGA) drawn from comparables. The particularity of mixed-use: residential and commercial rents do not share the same risk profile or duration, which can justify capitalizing the two uses separately.
The value of an income property is determined through capitalization of income. APCIQ's training on the value of an income property addresses precisely the calculation of market value and the overall capitalization rate (TGA) on a comparables basis, with the addition of a negotiation margin.
The challenge of the mixed-use building: residential and commercial income are not equivalent. A commercial rent may be higher per square foot but also more volatile — a commercial vacancy can drag on for months, whereas a dwelling generally re-rents quickly on the North Shore. Savvy buyers therefore often capitalize the two uses separately, with a distinct TGA for each stream.
To quickly estimate your building's potential, you can rely on our yield tools, which calculate net income, the GRM, and the TGA from a few inputs.
Why is the buyer pool smaller?
A pure plex attracts investors and owner-occupants. A mixed-use building requires understanding the commercial lease, commercial vacancy risk, GST/QST taxation, and often a stricter commercial mortgage. Many residential buyers and lenders step back, concentrating demand on seasoned investors.
This is the practical consequence of the two sections above. Selling a purely residential plex means addressing a broad market: rental investors, first-time buyers wanting to live in one unit and rent the others, experienced owners. Selling a mixed-use building means addressing a subset: buyers comfortable with the commercial side.
Financing also plays a role. A building where a significant share of income is commercial often falls under commercial mortgage rules, with stricter down-payment and qualification requirements than residential. Several residential lenders step back, further shrinking the list of solvent buyers.
"A mixed-use building rarely sells as fast as a comparable plex: fewer buyers, more checks, more demanding financing. The prepared seller — leases in order, income documented, tax allocation clear — keeps control of the process."
— ImmoMulti Team, direct buyer of income properties on the North ShoreHow do you prepare the sale of your mixed-use building on the North Shore?
The best defence against complexity is preparation. Before bringing your mixed-use building to market, assemble a complete file — it speeds up due diligence and reassures an already limited buyer pool.
Your mixed-use sale file
- All leases (commercial and residential) with remaining terms and renewal options
- Income and expense history to establish net operating income
- Price allocation between residential (exempt) and commercial (taxable) portions
- Verification of zoning and commercial use compliance
- Status of land registry entries (published commercial leases)
On the North Shore, a well-located mixed-use building on a busy artery remains sought after — but it is the organized seller who gets the best price and the shortest timeline. If you prefer to avoid the open market and its time on sale, a specialized direct buyer can submit an offer adapted to the particularities of mixed-use, with no commission.
To go further, see our guide to multiplex yield calculation, and our analysis of the North Shore real estate market in 2026. And if you are considering selling, request a direct offer.
Informational content only. Does not constitute legal or tax advice. Tax rules and rates can change; consult a notary and a tax advisor for advice specific to your building and transaction.
