In a resale purchase you are buying something that exists, you can inspect it, and the agreement is a standard form your agent and lawyer see constantly.

In a pre-construction purchase you are buying a promise to deliver something that does not yet exist, on terms the builder wrote. The agreement is the builder's own document, often long, and the parts that matter most to you are in the schedules rather than the first page.

That is not a reason to avoid it. A great deal of new housing in York Region is sold this way and plenty of buyers do well. It is a reason to treat the signing as the important moment, because almost everything is decided there and very little is negotiable afterwards.

The rest of this guide covers what is actually in those documents and what to do about it.

Under Ontario's Condominium Act, a buyer of a new condominium unit from a builder may cancel the agreement within ten calendar days with no penalty and a full refund of the deposit. The Home Construction Regulatory Authority, which licenses builders in this province, states this plainly in its own guidance for buyers.

The part people miss is when the clock starts. It does not start at signing. It starts once you have received the agreement of purchase and sale, the disclosure statement and the Condominium Buyers' Guide. During that period the builder must hold the unit for you.

What that period is for. It exists so a lawyer can read the documents before you are committed. That is the entire purpose, and it is the reason this is a genuine protection rather than a formality. A pre-construction agreement reviewed on day three is a different experience from the same agreement read for the first time two years later.

So the single most useful thing in this guide is this: get the complete package to a lawyer who does pre-construction work on the day you receive it. Not a general practitioner, and not after the period has run.

Two cautions. This right applies to new condominium units and is not a general cooling off period for every real estate purchase in Ontario, so do not assume it covers a freehold new build. And the precise requirements, including what must be delivered and how cancellation must be given, are legal matters. Confirm them with your lawyer and with the current guidance from the Condominium Authority of Ontario and the Home Construction Regulatory Authority.

In a condominium, there is usually a gap between the point at which your unit is ready for you to move in and the point at which the condominium corporation is registered and ownership can actually transfer. That gap is interim occupancy.

During it you live in the unit and pay the builder a monthly amount. According to the Home Construction Regulatory Authority, that amount covers interest on the unpaid balance of the purchase price, an estimate of the property taxes, and maintenance fees.

Here is the part that surprises people, and it is worth stating directly. Those payments are not mortgage payments and they do not go toward the purchase price. Your mortgage and your legal ownership begin at final closing, after registration. Everything paid during occupancy is gone.

Occupancy periods vary and can run for a meaningful stretch. Nobody can tell you in advance exactly how long yours will be, which is precisely why it needs to be in your budget as a risk rather than ignored because it is unknown.

What to do about it. Ask your lawyer to explain how occupancy is calculated in your specific agreement, ask what the builder's current estimate of the occupancy date and registration date is, and plan on the basis that you may be paying occupancy costs and still paying for wherever you live now if the timing slips. If you intend to rent the unit out during occupancy, check whether your agreement permits it, because many restrict or prohibit it.

A new home from a builder is generally subject to HST, which is not the case on an ordinary resale purchase. Rebates exist for eligible purchasers, and builders commonly quote a price that already assumes the buyer qualifies and assigns the rebate to the builder.

The trap is eligibility. The rebate available to someone buying a home to live in is not the same as the position of someone buying to rent out, and a buyer who does not qualify for the rebate the builder assumed can face a substantial amount payable at closing that was never in their budget.

The same applies if your intentions change between signing and closing, which over a multi-year build is not unusual.

This is accountant and lawyer territory and nothing else. Rules, rebate programs and eligibility conditions change, amounts depend on the price and the circumstances, and getting it wrong is expensive. Establish your position in writing before you sign, and raise it again if your plans change. No amounts or rates appear here deliberately.

Deposits on a new condominium must be held in trust. If the builder terminates the agreement, the deposit is to be returned, and where it is not, a claim can be made to Tarion under its deposit protection.

The point to take from this is not that you are protected. It is that the protection has a stated limit. Pre-construction deposits in this market are frequently well above the sorts of figures a protection scheme covers, which means part of your deposit may sit outside it.

No figure appears here because limits and rules change. Get the current coverage limit from Tarion directly, compare it against the deposit you are actually being asked for, and ask your lawyer what happens to the difference. That is a two minute calculation and most buyers never do it.

Ask your lawyer separately how and where your deposit will be held, and under what circumstances the builder may use it.

What pre-construction offers: a new building with new systems and a warranty, a deposit structure spread over time rather than due at once, the ability to choose finishes within what the builder offers, and a long runway before you need a mortgage.

What resale offers: you can see exactly what you are buying, you can have it inspected, you know the building's actual condition and the corporation's actual finances, you know what the fees really are rather than an estimate, closing is a known date, and there is no occupancy period.

The honest framing of the trade: pre-construction asks you to accept uncertainty about timing, cost at closing and the finished product, in exchange for newness and a payment structure that suits some buyers. Whether that trade is worth it depends on how much the uncertainty actually costs you, which is a question about your own circumstances rather than about the market.

One thing to be clear about: pre-construction is not reliably cheaper than resale, and buying it on the assumption that it is guaranteed to appreciate before closing is a speculation rather than a plan. If the appreciation is the reason for the purchase, say so to yourself plainly and size the risk accordingly. Our Richmond Hill condo buyer guide covers the resale side.

1. Letting the ten days pass without a lawyer reading the documents. The single most expensive mistake available in this transaction.

2. Budgeting the purchase price and nothing else. Adjustments, levies, HST exposure and occupancy costs all sit on top.

3. Treating occupancy payments as mortgage payments. They are not and they do not reduce what you owe.

4. Assuming the first date you are given is the closing date. Plan for it to move.

5. Assuming you can assign. It generally needs consent and may be restricted or charged for.

6. Assuming the HST rebate in the quoted price applies to you. It depends on your use of the property, and investors frequently sit differently from occupants.

7. Buying the rendering. Finishes, materials and layouts are governed by the agreement, not by the model suite.

8. Buying on expected appreciation. If that is the reason for the purchase, name it to yourself and size the risk rather than calling it a plan.