- A prenup that does not meet section 38 of the Family Property Act does not displace the default property rules.
- Common defects include a missing or shared-lawyer acknowledgment, no statement that the agreement continues after marriage, and a party who knew the marriage was void.
- Support and children's terms follow separate rules, so a valid property clause does not guarantee a waiver or parenting term will stand.
If you doubt your prenup, you probably want to know what, specifically, can make it fail. In Alberta, the most reliable answers come from the formal requirements in the Family Property Act.
This article walks through the defects the Act points to, explains what happens when an agreement fails, and flags areas where the answer depends on the facts and a lawyer should look at your documents.
This article covers the law of Alberta.
Why the formalities matter so much
A written agreement replaces the default property rules only if it is enforceable under section 38. If it does not meet section 38, it does not displace Part 1 of the Act. Enforceability turns on sections 37 and 38, and the Act has no separate section giving a judge a general power to set aside a compliant agreement as unfair.
Defects in the signing process
Section 38 asks for a written acknowledgment from each party, made apart from the other party. Check your agreement against this list:
- Each party acknowledged in writing that they are aware of the nature and effect of the agreement.
- Each party acknowledged that they understand their possible future claims and intend to give them up as the agreement provides.
- Each party acknowledged that they are signing freely and voluntarily.
- Each acknowledgment was made apart from the other party.
- Each acknowledgment was made before a lawyer other than the lawyer acting for the other party.
A common problem is one lawyer acting for both people. The acknowledgment must be made before a lawyer other than the one acting for the other party. A missing acknowledgment, or one made together with your partner, is the kind of gap that can leave the agreement unenforceable.
Defects in the wording
If the agreement was made before the marriage, it is unenforceable after the marriage unless it is clear that the parties intended it to apply or continue to apply after the marriage. This requirement applies only to agreements made before marriage, not to those made after.
A separate issue concerns whether the marriage or relationship itself was valid. It is unenforceable by a spouse who, when it was made, knew or had reason to believe the marriage was void. The same applies to a person who knew or ought to have known there was no valid adult interdependent relationship.
Pressure, missing information and unfairness
People often ask whether pressure to sign, incomplete information about your partner's finances, or a one-sided result makes a prenup invalid. The Act's own test centres on the acknowledgments, including that each person is signing freely and voluntarily and understands what they are giving up. The Act has no separate section letting a judge set aside a compliant agreement just because it is unfair.
Beyond that, how a court treats pressure, non-disclosure or an unfair result depends on the facts of the case. If any of these apply to you, gather your documents and speak with a lawyer rather than assuming the agreement stands or falls.
What happens if the agreement fails
The default rules can apply, and the court can still consider the terms of the agreement as one factor. For property acquired during the marriage that is not exempt, the court shall distribute it equally unless that would not be just and equitable. Exempt property, such as gifts from third parties, inheritances and property acquired before the marriage, is excluded at its market value, and the court distributes any increase in its value in a just and equitable manner.
| Part of the agreement | Separate test |
|---|---|
| Spousal support release | A court can depart from it if it is inequitable and a listed circumstance exists, including no independent legal advice |
| Child support | The agreement does not prevent a child support application |
| Parenting terms | No binding force over the court's best-interests assessment |
So one part of a prenup can be set aside or ignored while another part stands.
What to do next
- Find the signed agreement and both written acknowledgments.
- Note who each lawyer was and whom they acted for.
- Look for wording saying the agreement continues after the wedding.
- Note the date it was signed, because pre-2020 agreements are judged by the rules in force when they were made.
- Watch the deadlines for a property claim: an application based on one-year separation generally must be commenced within 2 years after the spouses separated.
A lawyer can review the documents and tell you how these points apply to your situation.
Frequently asked questions
Is a prenup invalid if only one of us had a lawyer?
Each party's acknowledgment must be made before a lawyer other than the lawyer acting for the other party. If one person made no acknowledgment before such a lawyer, the agreement may not meet section 38, which a lawyer can confirm.
Is a prenup invalid if it does not mention the marriage continuing?
An agreement made before marriage is unenforceable after the marriage unless it is clear the parties intended it to apply or continue to apply. That is why a prenup should say so expressly.
Can I challenge a spousal support waiver in my prenup?
A release is permitted by Alberta's Family Law Act, but a court may depart from the agreement if it is inequitable and a listed circumstance exists. One listed circumstance is that the challenging spouse had no independent legal advice. If your separation proceeds as a divorce, the Divorce Act also lets the court weigh any agreement about support alongside the spouses' circumstances and the objectives of a support order. The Justice Canada guide on spousal support describes complete waivers as often fairly easily overridden or set aside, especially where there are children.
Does a failed prenup mean all property is split equally?
Not automatically. Non-exempt property acquired during the marriage is divided equally unless that would not be just and equitable, and exempt property is treated differently.
Sources
- Family Property Act, s. 37(1) (Alberta King's Printer) — kings-printer.alberta.ca
- Family Law Act, s. 62(1) — kings-printer.alberta.ca
- Divorce Act, s. 15.2(1) and (4) — Justice Laws (federal)
- Department of Justice Canada, Spousal Support Advisory Guidelines: Revised User's Guide (Agreements) — justice.gc.ca
- Family Law Act, s. 53 — kings-printer.alberta.ca
- Divorce Act, s. 16(1)-(2) — Justice Laws (federal)
Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.
This is a family law question
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