A condition deadline arriving with the underlying work still unfinished is one of the most common moments in a live deal — and one of the easiest to mishandle. An extension and a waiver look similar from the outside, but they are legally different acts with different consequences, and confusing them is how a client ends up either stuck with no protection or stuck with no deal.
Key takeaways
The two options that arrive at a condition deadline get conflated constantly, and they are legally opposite acts. A waiver is something only the party the condition protects can do — typically the buyer, on a financing or inspection condition — giving up the right to rely on it, whether or not it was ever actually satisfied. An extension is different in kind: it changes the deadline itself, and because the deadline is a negotiated term of a signed contract, changing it needs the same thing that created it — agreement from both sides, in writing. One side cannot simply decide the clock has more time on it.
Treadstone Law’s guidance on conditions is explicit about the mechanics that apply to resolving a condition at all: fulfillment and waiver “need to be communicated in writing and delivered before the deadline”. An extension runs on the same logic — it has to be documented and it has to happen before the original deadline lapses, because once the deadline passes unaddressed, the condition — and the protection it offered — is no longer something either side can simply revive by agreeing informally afterward.
Ontario’s standard offer mechanics don’t leave a silent gap. The irrevocable-period logic that governs an unanswered offer applies structurally to an unaddressed condition deadline too: Treadstone Law’s guide on the irrevocable period notes that when a deadline passes with no response, “the offer dies automatically”, and the released party cannot later purport to revive it by accepting late. A condition deadline that simply lapses without a written extension or waiver exposes the deal to the same kind of automatic failure — which is exactly why an informal understanding between agents that “we’ll sort the paperwork out after” is not a safe substitute for a signed amendment before the clock runs out.
Agents on both sides sometimes treat an extension as a formality once the two principals have verbally agreed — a phone call, a friendly “sure, take the extra days,” and everyone moves on. The risk shows up later, not in the moment: if the deal goes sideways for an unrelated reason and ends up disputed, whether the condition was actually still alive at the point something else went wrong can turn entirely on whether a written amendment exists with a date on it. Treadstone Law’s conditions guide frames the general risk this way: once you’re past a deadline with nothing resolved in writing, you’re relying on an interpretation of what happened rather than a document that settles it. A one-paragraph amendment, signed by both parties, naming the new date and nothing else, closes that gap for the cost of a few minutes.
This is the leverage half of the question, and it’s a negotiation problem as much as a legal one. Asking the other side to agree to move a deadline tells them something didn’t go as planned — a lender needs more time, an inspector found something worth a second look, a status certificate arrived late. A seller under no legal obligation to agree can use that moment to extract a concession: a price adjustment, a shorter closing, the buyer dropping a different condition in exchange. The buyer’s countervailing leverage is whatever cost the seller would absorb by refusing — relisting, losing a buyer who is otherwise ready, or simply the deposit the seller keeps if the deal collapses instead of extending. Neither side’s position is fixed; it depends on how replaceable the deal actually is for the party being asked.
A related mechanism, mentioned in Treadstone Law’s conditions guide, sidesteps the request-an-extension problem entirely by planning for it in advance: an escape clause — sometimes called a “48-hour clause” — lets a seller keep marketing the property during a buyer’s condition period, and if a better offer arrives, gives the original buyer a short window to waive their condition or lose the deal. It doesn’t extend anything; it does the reverse, putting pressure on the conditional buyer to resolve their condition faster. Where one is in the offer from the outset, the extension conversation this article covers may not come up at all — the buyer is instead forced to a waive-or-walk decision on short notice if a competing offer surfaces.
A buyer’s financing condition is due to expire tomorrow, and the lender has said the appraisal is delayed by three business days through no fault of the buyer’s. The buyer’s agent asks the seller’s agent for a three-day extension. If the seller agrees, the correct next step is a written amendment to the Agreement of Purchase and Sale, signed by both parties, moving the specific date — not a text message confirming the informal understanding, and not the buyer simply waiving the condition on the strength of a verbal yes, which would give up the exit right the buyer still needs for those three days. If the seller declines, the buyer faces the deadline as originally written: waive without confirmed financing and accept the closing risk, or let the condition lapse and lose the deal on the terms already agreed. There is no fourth option where the deadline quietly moves without anyone signing anything.
Now vary one fact: instead of a delayed appraisal, the buyer’s lender has flatly declined the file and the buyer is scrambling to find a second lender. That’s a materially weaker position to negotiate an extension from, and the seller’s agent should recognize the difference — a documented processing delay with a lender still committed to funding is a very different risk than an open-ended search for a new lender with no confirmed appetite yet. A seller (and their agent) weighing whether to grant an extension is, in substance, being asked to re-underwrite the buyer’s financing risk without seeing the buyer’s file. Asking what specifically changed, and how confident the new timeline actually is, is a reasonable question for a listing agent to raise before recommending their client agree.
No. Only the party a condition protects can waive it unilaterally — and that gives up the right entirely, it doesn’t buy time. Moving the deadline itself needs the seller’s written agreement, because it changes a term both sides agreed to. See choosing which conditions to keep for what the condition is actually protecting while that decision gets made.
Treat it as not binding until it’s in writing. Treadstone Law’s guidance is specific that resolving a condition — and by the same logic, changing its deadline — needs to be communicated in writing and delivered before the original deadline, not confirmed informally after.
Then the buyer is at the original deadline: waive the condition and accept the risk, or let it lapse. See keeping a deal together during conditions for the practical options at that point, and mutual release, or fight it out for what happens if the deal doesn’t survive.
A short call can walk through whether an extension, a waiver, or letting it lapse actually protects your client best.
