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Custom home builder tax: the HST rebate, the self-supply rule, and the year the profit lands
For a builder, the T2 is the easier half of the tax file. The harder half is HST: which homes carry a new-housing rebate you can credit at closing, which buyers do not qualify, what a spec home costs you the day it becomes a rental, and how much tax is deferred inside land you are still holding. We prepare builder returns with those answers documented before each closing, not reconstructed afterward.
By the AnalytIQ Accounting team · Last reviewed: August 12, 2026
Spec profit is business income, and timing follows the closing
A spec home is inventory, so the profit on its sale is fully taxable business income, never a capital gain, whether the builder is a corporation or an individual. The profit is recognized when the sale closes, which makes the fiscal year-end a real planning lever: a year-end that falls just before the spring closing season moves a whole cohort of profit into the following year's return. Choosing a fiscal year-end for your corporation walks through that decision.
Custom contracts follow contractor rules instead. Longer builds are reported on percentage of completion; CRA's long-standing contractor guidance has accepted the completion method for contracts expected to run under two years, which fits many custom homes, though the method must be applied consistently once chosen. Holdbacks are excluded from income until they become receivable after the lien period, and HST on them is deferred on the same logic. A warranty provision booked on the financial statements is added back on the T2 and deducted only when the warranty work is actually done, so the statements and the return show different numbers on purpose.
The new housing rebate: three different homes, three different forms
The rebate belongs to the buyer, but the builder handles most of the paperwork and carries the risk of getting it wrong. At the time of writing the federal component is 36 percent of the GST paid, capped at $6,300 and phased out entirely at a $450,000 price, while the Ontario component refunds 75 percent of the provincial portion up to $24,000 with no phase-out. A first-time buyer GST rebate announced federally in 2025 changes the arithmetic for qualifying purchasers, so we confirm the rules in force before any agreement is priced.
| Situation | Who claims | Form | What the builder must do |
|---|---|---|---|
| Spec home sold to a buyer who will live in it | Buyer, assigned to the builder | GST190 with the Ontario schedule | Credit the rebate at closing, claim it on the GST34, file the signed application |
| Custom home on the client's own lot | The client, after completion | GST191 with the construction worksheet | Charge HST on the contract and provide an itemized cost summary |
| Spec home sold to an investor who will rent it | Buyer, later | GST524 rental rebate | Collect full HST at closing; no credit |
| Buyer not eligible (vacation use, corporate purchaser) | Nobody | None | Collect full HST and document why |
The builder's exposure is the credited rebate: if you credit it to a buyer who does not use the home as a primary place of residence, CRA can deny it and look to you for the amount. We keep the signed application, the buyer's declaration and the closing documents together on each lot's file.
Self-supply: the tax bill for changing your mind
When a spec home will not sell and you rent it out, or move into it, the Excise Tax Act treats you as having sold it to yourself and bought it back at fair market value on the day of first occupancy. HST on that value goes on the return for that period, the input tax credits you claimed during construction stay claimed, and the home is used residential property for HST purposes from then on. If the tenant will be there long-term, a new residential rental property rebate can recover part of the tax, and an appraisal dated to the occupancy date supports the value used.
An individual who builds a home primarily as a residence for themselves or a relation, and claims no input tax credits along the way, can fall outside the rule under the personal-use exception, but a builder who has already claimed credits usually cannot retreat into it. The choice to rent a stale spec rather than cut the price is therefore a tax decision, and we model both paths before the lease is signed.
Land, lots, and the return a lender will read
Buying a lot from a registrant developer means self-assessing the HST on your own return and claiming the offsetting credit in the same period; buying from an individual selling personal land is often exempt, and the difference belongs in the offer, not in the year-end file. Interest and property taxes on vacant land held as inventory, and soft costs during the construction period, are capitalized into the cost of the lot and house rather than deducted currently, so a builder carrying several lots can show a small taxable income now and a large tax bill two years later when they close. Assignment sales of new homes have been fully taxable since 2022, which matters when a buyer flips a purchase agreement before closing.
Two structural points complete the file. Builders who use a separate corporation per project share one small business deduction across the associated group, and instalments have to be planned around lumpy closings rather than a steady monthly profit; when a corporation has to pay tax instalments covers the thresholds. Construction lenders, and the HCRA at licence renewal, may ask for financial statements, so the year-end package is often a review engagement rather than a compilation. Builders with US-citizen clients or US-sourced materials should read our cross-border guide for custom home builders; the general engagement is described on our tax services page.
Source: CRA — RC4052, GST/HST Information for the Home Construction Industry.
Common questions.
Is the profit on a spec home a capital gain?
No. A home built to sell is inventory, so the profit is fully taxable business income in the year the sale closes, whether you build personally or through a corporation.
What happens to HST if I rent out a spec home instead of selling it?
The self-supply rule deems a sale to yourself at fair market value on first occupancy, and HST on that value is due on the return for that period. A rental rebate may recover part of it, and an appraisal on the occupancy date supports the number.
Can I deduct the interest on lots I'm holding for future builds?
Generally not in the year paid. Interest and property taxes on vacant land held as inventory are added to the cost of the land and recovered when the home is sold.
Related reading
Tax filed the way a builder's year actually runs.
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