The client
A self-employed parent in Camrose bought a $455,000 home at 10% down, carrying $8,700/month of their own income following a slow prior year now behind them.
Purchase price
$455,000, Camrose
10% down, insured
Self-employed parent's income
$8,700/month
Relied on alone for the ratios
Guarantor
Adult child, no ownership interest
Not registered on title; contributes no income
Other debt
$245/mo car loan
The problem
The parent's own income comfortably cleared the ratios -- the file was never short on paper. What the lender's own covenant-strength policy for self-employed files coming off a volatile income year actually called for was an additional party with stronger, more established net worth, regardless of whether GDS and TDS themselves were fine.
What the policy needed, and what it did not
- ▸Not more income -- the parent's own $8,700/month already supported the ratios on its own
- ▸Not title -- the adult child had no ownership interest and no wish to appear on title
- ▸Extra covenant strength -- satisfied by the lender's own net worth mortgage program overlay, met by a guarantor's secondary obligation, not anyone's primary liability
The parent's adult child agreed to help, but wanted to know exactly what they were signing up for before agreeing to anything.
The numbers
The guarantor's addition changed nothing about the arithmetic -- that was the entire point of using a guarantor rather than a co-borrower.
| Qualifying on the parent's income alone | Amount |
|---|---|
| Base mortgage (90% of purchase price) | $409,500 |
| CMHC premium (3.10% at 90% LTV) | +$12,694 |
| Total insured mortgage | $422,194 |
| Ratio check at the qualifying rate | Figure |
|---|---|
| Payment at the qualifying rate (6.95%), 25 years | $2,944/mo |
| GDS (payment + $320 tax + $120 heat) ÷ $8,700 income | 38.9% |
| TDS (GDS numerator + $245 car loan) ÷ $8,700 income | 41.7% |
38.9% GDS and 41.7% TDS sit comfortably inside CMHC's 39% and 44% maximums on the parent's income alone -- the guarantor's own income was never part of this calculation, and the lender's covenant-strength policy was satisfied entirely separately from it.
The solution
A mortgage associate licensed under Alberta's Real Estate Act Rules structured the file so the guarantor's role was clear from the outset: covenant strength, not qualifying income.
First, confirmed the parent's own income cleared GDS and TDS on its own, with no guarantor income folded into either calculation at any point.
Second, added the adult child as guarantor only -- never registered on title, contributing no income to the ratios, and assuming a secondary, contingent obligation that would only ever be called on if the parent defaulted -- a materially different, and lesser, exposure than a covenantor's primary joint-and-several liability or the informal role most people mean by co-signer or guarantor.
Third, explained the distinction plainly to both parent and child before either one signed, so the guarantor understood exactly what standing behind the file did and did not expose them to.
The outcome
The purchase funded insured at 38.9% GDS and 41.7% TDS on the parent's own income alone, with the guarantor's role satisfying the lender's covenant-strength policy without changing a single figure in the ratios.
Both ratios sit comfortably inside CMHC's 39% GDS and 44% TDS maximums; the file was never close to either ceiling, with or without the guarantor.
What to take from this file
- 01A guarantor's income does not get added to GDS or TDS the way a covenantor's does. Adding a guarantor changes covenant strength, not the ratio math.
- 02A guarantor's obligation is secondary and contingent; a covenantor's is primary and joint-and-several. Explain the difference in plain terms before anyone signs -- 'co-signer' means different things to different people.
- 03A lender's own covenant-strength or net-worth policy can call for a guarantor even when the ratios already clear. That policy is the lender's own overlay, not a published, universal rule.
- 04A guarantor never has to appear on title. Being added purely for covenant strength does not require, or usually even involve, any ownership interest in the property.
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.
- ▸CMHC — Purchase (Mortgage Loan Insurance) — default-insurance premium schedule by LTV band (25-year amortization).
- ▸CMHC — CMHC Home Start — minimum down payment tiers (5%/10%) and the $1.5M insured price cap.
- ▸OSFI — Minimum qualifying rate for uninsured mortgages — the minimum qualifying rate — greater of contract rate + 2% or 5.25%.
- ▸CMHC — CMHC Reviews Underwriting Criteria — GDS 39% / TDS 44% maximums and the 600 credit-score floor for insured files.
- ▸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:
- ▸4.95% contract rate — rates move daily; not a quote.
- ▸the lender's own covenant-strength/net-worth policy for self-employed files after a volatile year — each lender sets its own overlay policy on top of GDS/TDS; there is no published, universal rule requiring a guarantor in this situation.
- ▸Alberta closing costs — Alberta has no land transfer tax; Land Titles Office registration fees apply on a sliding scale, but a specific total dollar figure is not independently verified and is omitted here.
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.