The short version
- An as-complete appraisal values the property as it will be once the planned work is finished, using your drawings and your contractor's quote.
- On a construction mortgage like the Blueprint Build Plan, the mortgage can be up to 80% of that finished value.
- The quality of what you hand the appraiser drives the number. Vague plans and round-number quotes make for cautious values.
- A low appraisal is a budgeting problem, not a dead end. You can trim the scope, add funds, or rethink the project.
A value for a property that does not exist yet
Most appraisals answer a simple question: what is this property worth today? An as-complete appraisal answers a harder one: what will it be worth once the work you are planning is finished? On a construction or renovation mortgage, that second number is the one that matters.
The appraiser still inspects the property as it stands. But the value they report is for the finished version, built from your drawings, your specifications and your contractor's quote, and compared against finished properties like it. A house worth $625,000 today might appraise at $925,000 as complete once a garden suite is added, if the plans and the local comparables support it.
That is why lenders use it for projects like basement apartments, garden suites, additions and full rebuilds. Lending on today's value alone would leave the new unit out of the picture entirely.
What the appraiser needs from you
An appraiser can only value what they can see on paper. The better the package, the more confident the number. In practice that means:
- Drawings. Floor plans and, for a new structure, a site plan showing where it sits on the lot.
- An itemised contractor quote. Broken down by trade, with a contingency line. A single round number invites a cautious reading.
- Specifications. Finishes, fixtures and mechanicals. A suite with its own laundry and a heat pump is not the same product as one without.
- The permit position. Whether the permit is applied for, approved or still to come, and what your municipality allows on the lot.
- A realistic timeline. On the Blueprint Build Plan the work has to be finished within 6 to 12 months of closing.
The City of Kitchener makes the same point from the other side. Its additional-unit guide tells homeowners to assemble a design and building team and to develop a detailed budget and financing plan before applying for a permit. That same package is what the appraisal is built on.
How the number sizes your mortgage
On the Blueprint Build Plan, the mortgage can be up to 80% of the as-complete value. Here is how that works on an illustrative project.
- Home value today: $625,000, with $440,000 owing
- Planned garden suite: $300,000
- As-complete appraisal: $925,000
- Up to 80% of that: $740,000, which covers the $440,000 owing plus the $300,000 build
Now suppose the appraisal comes in at $875,000 instead. Eighty per cent of that is $700,000, which leaves $40,000 of the build uncovered. Nothing else about the project changed. The value did, and the budget moved with it.
When the value comes in low
A low as-complete value is common and rarely fatal. It usually means one of three things: the scope costs more than the finished property will support, the plans left the appraiser guessing, or local comparables for that kind of property are thin.
The fixes follow from the cause. You can trim the scope so the budget fits under the value. You can add funds of your own to cover the gap. You can clarify the plans and specifications if something was missing. Or you can step back and ask whether a different project, such as a basement conversion instead of a detached suite, is the better fit for the lot.
What not to do is sign a construction contract first and hope the appraisal catches up. The order matters.
After approval: inspections and the holdback
The appraisal does not end at approval. As the work goes on, an inspector confirms the percentage of the project that is complete, and each draw is paid to you, the owner, on that basis. Ontario's homeowner guide makes the parallel point for building permits: required inspections happen during construction, not just at the end.
On the Blueprint Build Plan, each draw is paid less a 15% holdback that the lender keeps until the final inspection confirms the work is finished. You carry that amount in the meantime, so it needs to be available before the build starts.
What an as-complete value is not
It is not a promise of what the property will sell for, and it is not a forecast of the rent a new unit will earn. It is a lender's opinion of value, for lending purposes, on the plans as submitted. If the plans change materially during the build, expect the lender to want to know.
Nearly thirty years in Canadian financial services, based in Waterloo Region and working across Ontario. Most people are handed a product — you deserve a plan.
How a lender treats a new unit, what an appraiser will value it at, and what your municipality permits all vary by property and by file. Everything here is illustrative and subject to lender approval and final terms.
Sources: City of Kitchener — Additional dwelling units · Government of Ontario — Add a second unit in your house · City of London — Additional Residential Units