Treadstone Associates
Case File № 132 · Rental & Investment

Two units, one ratio problem

add-back vs. offset on a Drummondville duplex purchase

A straight investment-duplex purchase in Drummondville, both units rented from day one, saw TDS swing from 54.1% under a bank's add-back treatment to 30.8% under an offset lender — the same file, the same two leases.

QuebecUninsured · conventional purchaseFiled August 7, 20265 min read
54.1%

TDS under the bank’s add-back treatment — declined

30.8%

TDS under the offset lender — approved

$5,010

Quebec welcome tax due in cash at closing on the $460,000 purchase

Anonymized illustration. The borrowers, dollar figures, and rates in this file are an illustrative composite — no real client is identifiable, and any rate shown is illustrative, not a quote. The rules are real: every regulatory figure is cited to its source in the Sources section, and the math computes exactly as shown.

№ 01

The client

A single applicant working in the Drummondville market wanted a straight investment property: no plan to live in either unit, both sides rented from closing day. A non-owner-occupied investment-property mortgage like this is priced and underwritten differently from an owner-occupied purchase, and with rental vacancy tight across Quebec, both units already had tenants lined up before the offer went in.

Applicant

Single applicant, salaried

$5,000/month gross income

Purchase price

$460,000 duplex, Drummondville

Non-owner-occupied from closing

Down payment

$92,000 — 20%

Conventional; structured for a non-owner-occupied purchase

Unit A lease

$1,150/month

Signed

Unit B lease

$1,050/month

Signed; heat is tenant-paid under both leases

Existing debt

$410/month auto loan

Carried in both scenarios below

The purchase, before either lease enters the ratio math:

Purchase structuringAmount
Purchase price$460,000
Down payment (20%)−$92,000
Loan amount$368,000
Quebec welcome tax (droits de mutation) due at closing$5,010
№ 02

The problem

The applicant's own bank applied its standard add-back policy to both leases: half the combined rent added to income, full carrying costs charged against the file as a liability — the same treatment a lender would apply to a rental kept alongside a new primary residence, even though here there is no primary residence in the file at all.

The add-back arithmetic

  • Income used: $5,000 + $1,100 (half of the $2,200 combined rent) = $6,100/mo
  • Liabilities: $2,888 full carrying cost + $410 car loan = $3,298/mo
  • TDS: $3,298 ÷ $6,100 = 54.1% — over the 44% ceiling. Declined.

A single applicant's own income was never going to carry a $460,000 duplex on its own, and the add-back treatment barely credits the two signed leases that were meant to do exactly that.

№ 03

The numbers

At 20% down, the loan is $368,000; the file qualifies at the minimum qualifying rate against the actual contract rate.

Rate and paymentAmount
Contract rate — 5-year fixed conventional (illustrative, not a quote)5.09%
Minimum qualifying rate — greater of contract + 2% and 5.25%7.09%
Monthly P&I at the qualifying rate — the ratios run on this$2,598
Monthly P&I at the contract rate — what is actually paid$2,159

Full carrying cost on the duplex

Carrying costMonthly
P&I at the qualifying rate$2,598
Property tax$290
Full carrying cost (heat is tenant-paid)$2,888

Both units are leased for a combined $2,200/month. The 50% add-back and 80% offset compared below are illustrative of the two common structures; each lender publishes its own.

TDS lineBank A — 50% add-backLender B — 80% offset
Income used$6,100 (incl. half of rent)$5,000 (no rent added)
Full carrying cost / shortfall$2,888 (full)$1,128 (shortfall after offset)
Car loan$410$410
TDS54.1%  ✗30.8%  ✓

The 80% offset applies the $2,200 combined rent against the duplex's own $2,888 carrying cost first, leaving only a $1,128 shortfall in the liabilities; the same file swings 23 TDS points depending purely on which lender's rental-income policy is used.

№ 04

The solution

A courtier hypothécaire (mortgage broker) licensed by the AMF re-ran the file through a lender whose published policy offsets both units' rent against the duplex's own carrying costs rather than treating the property the way a bank treats a rental kept alongside a primary residence.

Because the file had no primary-residence income cushion to fall back on, the submission leaned entirely on the strength of the two leases:

Signed 12-month leases for both units
Two years of T1s and NOAs for the applicant
90-day history of the $92,000 down payment
Purchase agreement and property tax assessment
Confirmation the applicant would not occupy either unit

The lender's underwriter cared most about the leases being real, signed, and at market rent — not about padding the applicant's own income, which the offset treatment made largely irrelevant to the outcome.

№ 05

The outcome & the closing math

Approved and funded: $368,000 conventional at 80% LTV, 25-year amortization, 5-year fixed term, both units tenanted at closing.

Cash due at closing (beyond the down payment)Amount
Quebec welcome tax (droits de mutation) on $460,000 — 0.5% / 1.0% / 1.5% brackets$5,010
Legal fees and adjustmentsvaries

The lender also required a 90-day paper trail on the $92,000 down payment on top of proof of funds for the welcome tax, which the same bank statements demonstrated.

№ 06

What to take from this file

  • 01A straight investment purchase has no income cushion. Without a primary residence in the file, the rental-income treatment is not a nice-to-have — it decides the file outright.
  • 02The add-back vs. offset gap widens when the property is 100% rental. This file swings 23 TDS points on identical leases, wider than a comparable file with a personal-residence income base to fall back on.
  • 03Every dollar of closing cash matters more on a thin-margin investment file. Quebec's welcome tax added $5,010 before legal fees, and the lender still wanted a full 90-day trail on the down payment.
  • 04A decline is a statement about one lender's rental policy, not the file. The same two leases and the same applicant qualified comfortably once matched to an offset lender.

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.

Illustrative in this file — lender-specific, not rules:

  • 5.09% contract rate — rates move daily; not a quote.
  • 20% down / conventional structuring — each lender sets its own down-payment requirement for a non-owner-occupied purchase.
  • 50% add-back / 80% offset treatments — each lender publishes its own rental-income policy.
  • $290/mo tax estimate, tenant-paid heat — lender-standard estimate and lease terms specific to this file.

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.

First published 7 August 2026Rules last verified 7 August 2026Next scheduled review 7 February 2027

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.

Treadstone fulfillment

Files like this are daily work for our desk.

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