The client
A separating Port Hope couple holds a $620,000 matrimonial home against a $310,000 joint mortgage. Years before the wedding, both signed a marriage contract with independent legal advice on each side -- a document neither had looked at closely since.
Home value at separation
$620,000
Port Hope
Existing joint mortgage
$310,000
Current throughout
What both spouses assumed
Net equity split 50/50
$155,000 each way
What the marriage contract actually says
A fixed $75,000 buyout
Signed pre-marriage, independent legal advice both sides
The problem
Both spouses assumed the buyout would be the usual math: net equity divided by two. Under Ontario's Family Law Act, spouses are free to contract out of that default equalization scheme entirely -- and this couple had, years before the wedding, with a marriage contract that fixed the separation buyout at a specific dollar figure rather than a share of whatever the home turned out to be worth.
Why a contractually fixed figure isn't automatically enforceable
- ▸Ontario law lets spouses displace the default 50/50 equalization scheme by domestic contract, but only if the contract itself is validly executed
- ▸Both parties need to have had independent legal advice, signed voluntarily, and made reasonably full financial disclosure at the time
- ▸A contract missing any of those isn't automatically void, but it becomes vulnerable to a challenge that could send the file back to a fresh 50/50 calculation
This is a different problem than a family-patrimony or premarital-equity exclusion applying automatically by statute -- here, nothing excludes anything by default; the contract itself is the only reason the buyout isn't simply half of today's equity.
The numbers
The math was simple once the contract's own figure, not the market value, was confirmed as the governing number.
| The naive 50/50 split vs. the contract's own figure | Amount |
|---|---|
| Home value at separation | $620,000 |
| Existing joint mortgage | $310,000 |
| Net equity | $310,000 |
| Naive 50/50 half | $155,000 |
| Marriage contract's own fixed buyout | $75,000 |
| Refinance needed | $385,000 |
| Qualifying at the stress-tested rate | Figure |
|---|---|
| Minimum qualifying rate on a 4.90% contract rate | 6.90% |
| Payment at the qualifying rate, 25 years | $2,673/mo |
| TDS (payment + $310 tax + $140 heat + $270 car loan) ÷ $8,600 income | 39.5% |
Had the naive $155,000 half governed instead, the refinance would have needed to raise $80,000 more than the contract actually required -- a materially larger mortgage the family had never budgeted for, even as home prices nationally have moved well past what they were when the contract was signed.
The solution
Family counsel and a mortgage agent worked the file in the right order: confirm the contract's validity first, then size the refinance to whatever figure actually survives that review.
First, confirmed both parties had independent legal advice at the time of signing. Each spouse's own lawyer's file from years earlier still had a signed certificate confirming it.
Second, confirmed the contract's financial disclosure was reasonably complete at the time. Neither party had hidden significant assets or debts when the contract was negotiated.
Third, sized the buyout refinance to the contract's own $75,000 figure, not the current 50/50 equity split. A refinance sized to the naive half would have raised $80,000 more than the file actually needed.
The outcome
The marriage contract held up on review, and the refinance funded at 4.90% covering the existing balance plus the contract's own $75,000 -- not a fresh 50/50 split of today's equity. TDS settled at 39.5%.
A marriage contract's fixed figure is only as reliable as its own execution -- a contract missing independent legal advice on either side would have been vulnerable to challenge, and the file would have had to plan for the larger, market-linked number instead.
What to take from this file
- 01A validly executed marriage contract can fix a buyout figure outright. Ontario's Family Law Act lets spouses contract out of the default 50/50 equalization scheme entirely, not just adjust it.
- 02Validity is not automatic. Independent legal advice on both sides, voluntary signing, and reasonable financial disclosure at the time are what make a domestic contract's fixed figure reliable.
- 03Don't size a refinance to current market value before checking for a contract. This file needed $80,000 less than a naive 50/50 split would have suggested.
- 04Ask early whether a couple signed a marriage or cohabitation contract, even years before the wedding. A document neither party has looked at in years can still govern the entire buyout.
- 05A contract that doesn't survive review sends the file back to the default formula. Confirming validity isn't a formality -- it's the fact the whole refinance size depends on.
Sources
Every regulatory figure in this file traces to one of these primary sources. Client details and anything that varies by lender are illustrative, as flagged below.
- ▸OSFI — Minimum qualifying rate for uninsured mortgages — the minimum qualifying rate — greater of contract rate + 2% or 5.25%.
- ▸Provincial/territorial mortgage-broker legislation fetched directly (bclaws.gov.bc.ca, legisquebec.gouv.qc.ca, fcaa.gov.sk.ca, web2.gov.mb.ca, nslegislature.ca, assembly.nl.ca) plus FCNB's own site for NB and CanLII's index for PE — see notes for per-province method — provincial mortgage regulators and licence titles.
Illustrative in this file — lender-specific, not rules:
- ▸4.90% contract rate — rates move daily; not a quote.
- ▸the marriage contract's own fixed figure — each domestic contract sets its own terms; this dollar figure is illustrative of this file only, not a formula.
- ▸the total debt service figure — this file is an uninsured refinance, so there is no CMHC ratio ceiling -- the number is informational.
Authority & provenance
How this case file was built
We publish the origin, the verification method and the reviewer for every case file, so you can judge how far to trust it before you rely on it with a client.
Where it comes from
Derived from files handled by Treadstone’s fulfillment desk and from scenarios contributed by partner brokerages. Names, employers, exact amounts and dates are changed so no client or file is identifiable.
Provenance: Composite — a pattern seen repeatedly on fulfilled files, not a single transaction.
What is verified
Every regulatory figure traces to a primary source listed above and was checked against it on the date shown. The arithmetic is recomputed by machine on every rebuild.
Anything that varies by lender is labelled illustrative rather than stated as a rule.
Who reviewed it
Reviewed for Canadian regulatory accuracy before publication, and re-checked whenever a cited rule changes.
Reviewed by: Nicholas Parson, Treadstone Associates — reviews every case file before publication.
This case file is professional reference material for licensed mortgage professionals. It is not advice to a borrower, and it is not a lender commitment. Insurer rules, qualifying rates and provincial taxes change — confirm the current position with the insurer, regulator or lender before you rely on any figure here in a live file.