How Appraisers Measure Square Footage (and Why Listings Differ)

Square footage is one of the most important numbers in an appraisal, and one of the most common sources of confusion. A buyer sees one figure on a listing, another on builder plans and a third in the appraisal report. This article explains how appraisers measure homes in Canada, why the figures often differ, and how the different parts of a home are treated.

Above-grade living area

For detached homes, appraisers generally measure the above-grade living area from the exterior walls. That means the finished, heated space that is entirely above ground level. The appraiser measures the outside of the house, sketches the footprint, and calculates the area of each floor.

Measuring from the outside is consistent and practical. It includes the thickness of exterior walls, so exterior measurements are slightly larger than the sum of the interior room sizes. Using one consistent method means homes can be compared fairly.

What is included and what is not

• Included: finished, heated living space on the main floor and upper floors.
• Not included in above-grade area: basements, attached garages, unheated porches and sunrooms, decks and open-to-below areas such as two-storey foyers.
• Reported separately: basement area and its level of finish, garage size, and any other notable spaces.

Basements

Basement space matters a great deal in Manitoba, where most homes have one. But buyers do not value basement space the same way they value above-grade space, even when it is nicely finished. Ceiling height, natural light and the feel of below-grade space all affect how buyers see it.

For that reason, appraisers report basement area separately and describe its finish. A 1,100 square foot bungalow with a fully developed basement is described that way, not as a 2,200 square foot home. The basement development is then valued on its own terms, using evidence from comparable sales.

Split-levels and bi-levels

Split-levels, very common in Winnipeg suburbs built in the 1960s to 1980s, can be tricky. Appraisers look at which levels are above grade and which are partly below. A lower level that is substantially below ground is usually treated as basement space, while levels that are at or above grade count as living area. Bi-levels, where the lower floor is partly sunken with large windows, are handled the same way. Consistency with how comparables are measured is the key.

Condominiums

Condominium units are measured differently from houses. Appraisers often rely on the unit's documented area, such as the area shown in condominium plans or by the developer, and confirm that it is reasonable on site. Different buildings may use different conventions, which is one reason appraisers compare condos primarily with sales in the same or similar buildings. See our article on condo appraisals for more.

Why the listing figure may differ

Listings often show a different square footage from the appraisal. Some common reasons:

• the listing combines above-grade and basement space into one figure
• the figure comes from builder plans or old records rather than a measurement
• an addition or renovation changed the footprint since the last measurement
• a sunroom or enclosed porch was counted even though it is unheated
• interior measurements were used instead of exterior

None of these necessarily means anyone made an error; they may simply use different methods. But for an appraisal, the method has to be consistent with how the comparable sales are measured.

Why it matters for value

Size is a major driver of price, so an error of a few hundred square feet can change the analysis. If a comparable sale is listed at a much larger size than it actually is, using that figure without checking would distort the adjustment. Appraisers measure the subject property themselves and check comparable sizes against reliable records wherever possible.

It is also why price per square foot is only a rough guide. Two homes with the same size can sell for very different prices because of location, condition, lot and basement development.

Additions and unusual spaces

Additions are measured as part of the home if they are finished, heated and of similar quality to the rest of the house. Converted garages, three-season rooms and lofts are judged on whether they function as true living space and how the local market treats them. If a space was converted without permits, the appraiser may note it and treat it carefully.

Rural homes and outbuildings

On acreages, the home is measured the same way, and each outbuilding is measured and described separately. A heated shop is not living area, but it can contribute significant value, and the report will show its size and characteristics.

What you can do

If you have plans, a real property report or documentation of an addition, have it available for the appraiser. If you believe the square footage in a report is wrong, ask how it was measured. Appraisers are happy to explain their sketch and calculations.

Older homes and renovations over time

Many Manitoba homes have been altered several times over the decades. A 1920s Winnipeg house may have a rear addition from the 1960s, an enclosed porch from the 1980s and a converted attic. Records may not reflect any of these changes, which is why appraisers measure on site rather than relying on old figures. Where an attic or half-storey has sloped ceilings, only the area with reasonable headroom is typically counted as living space, and the appraiser describes how it was treated so the comparison with other sales stays fair.

Accurate measurement, reliable value

Every appraisal from Burley Appraisals includes an on-site measurement and a sketch of the home. We serve Winnipeg and Southern Manitoba. Order an appraisal online.

Frequently asked questions

This article is general information, not legal, tax or financial advice. Speak with a qualified professional about your situation.