Missing square feet in Measurement

I am a real estate agent here in beautiful BC and mostly doing Iguides for our own listings… Using the Planix system… Seems like every one I measure comes up short compared to the strata plan or BC assessment… Am I doing something wrong with the wall thickness usually 6 or 8 inches, or something else I should be doing. Any advice greatly appreciated as I have a couple of commercial shoots coming up and I need to be accurate…

The wall thickness can definitely affect it. But depending the property size it wouldn’t be a ton IMO. I do 8 on every property and have never had an issue.

im not sure how (inaccurate) it could be. If its within a few % i would argue maybe thicker walls or not scanning areas that they are counting as Sq/ft.

As far as I understand Wall thickness should have nothing to do with the square footage. The system is measuring the inside surfaces of the walls. So if your walls are 4 ft thick or 2 inches thick the square footage of the building will / should be the same. The wall thickness is simply used to determine the main building exterior.
Main Building Interior: 1120.35 sq ft
Main Building Exterior: 1191.82 sq ft

The exterior area will never be 100% accurate because it is based on 1 measurement. The thickness of the wall where you measure it - generally the front door. In a brick front house with vinyl siding on the other 3 walls you will have a 9-10 inch wall on the front and a 7 inch wall on the other 3.

If your interior measurements are smaller than the numbers on the assessment I would say the assessment is based on exterior size and is not a valid comparison.

Sorry i forgot to mention that, yes the only number that should be effected by the wall thickness is the

Main Building Exterior: 1191.82 sq ft

It’s not unusual for the iGuide square footage to come out less than a previously stated total due to inconsistencies in the way measurements have been taken in the past. In Alberta, we now have to abide by RECA regulations in order to standardize all of this.
I noted that the BC Financial Services Authority mentions some of this at this document: https://www.bcfsa.ca/industry-resources/real-estate-professional-resources/knowledge-base/practice-resources/property-measurements
One item I noted was that for attached units, the outside dimensions normally used include the centre line of common walls. (Don’t know what they do for exterior walls on attached units.) In Alberta, the RECA requirement is that interior measure only is used for attached units. iGuide generally uses the RECA standard for all Canadian residential measure, so things like this could definitely be affecting your “expected” square footage.
For detached properties, RECA requirement is to include the exterior wall thickness.
The full methodology for RECA measuring is incorporated into iGuide’s measuring practice and can be found here: https://www.reca.ca/wp-content/uploads/2018/07/Guide-to-the-Residential-Measurement-Standard-Alberta.pdf
Both interior and exterior square footage calculations are in your measurement report though, so whichever is required - if BC has such a requirement - or more common for your area, is the one to use, I’m guessing.

Thanks to all that responded. Great advice that I can and will use.

The RMS standard here in Alberta is very specific, and unless specified otherwise (e.g. the ANSI standard) that’s what the iGuide drafters use.

Whenever there’s been a discrepancy between expected square footage and the reported square footage provided by iGuide, it’s because the expectation was wrong. e.g. builders that don’t abide by the RMS standard, old listing information from before the RMS standard was established, human error from hand-measurements, etc.

If a client ever has questions about this, refer them to the Method of Measurement page at iGUIDE | Method of Measurement.

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Is that how it works in your area? In Alberta, according to the RMS standard, it has to be an accurate wall thickness measurement, and it can vary from 4-6", though I’ve seen as thick as 12".

Here in Alberta, the wall thickness certainly will affect the square footage for standalone properties.

The measurements are done using interior data with the wall thickness square footage calculated and added on. e.g. the difference between interior and exterior square footage.

I’ve been doing a lot of attached dwellings lately here in BC. Here’s my verbiage with the agent. “iGUIDE very accurately measures interior drywall-to-drywall room dimensions and total interior area. We add the full wall thickness to arrive at total exterior square footage. Because the strata will apportion some of the common-walls and even exterior walls to common area or neighbor, my report usually shows a larger total area for the exterior and smaller for the interior. I recommend reporting the strata square-footage on your listing, because that’s what their condo fees are based on.”

EVERYBODY, responds, “cool, ya, well we always state that measurements are approximate…”


Thanks everyone… I now have the information I need… You are all terrific and glad to be part of this group… Very helpful… Doc

Every client I ever asked always told me 8’’ so i never questioned their many years of real estate knowledge. But maybe iv been wrong this entire time lol

Not familiar with these as we are in Ontario but if it is anything like MPAC or Builder plans you are doing nothing wrong. MPAC here which is used for tax assessment are highly flawed measurements done from the exterior a good 10 to 15% off at times. MPAC measurements aren’t legal to be used on TRREB.

Take a condo for example builder claims walls as does MPAC but the walls aren’t owned by the unit owner they are sold to the Condo Corp which retains them, but yet you are taxed for those walls. Everyone can lie about the sq ft numbers but only the agent and us are liable if we use the irregular ones from MPAC or the builder.

Considering they sell condos by the sq ft it is a highly shady practice that legislatures here have yet to crack down on as they have in Alberta. I welcome the day they do, the iGuide measurements are highly accurate.

Every client I ever asked always told me 8’’ so i never questioned their many years of real estate knowledge. But maybe iv been wrong this entire time lol

I don’t know how it works in BC. Maybe you’re right for your area.

Do you guys run into situations where the accuracy needs to be very high? Most of my clients seem very relax about it. And i always believed that its hard to argue that the measurements aren’t close when its a laser and a machine which cuts out a large portion of error.

Do you guys run into situations where the accuracy needs to be very high?

Definitely. In Alberta, accuracy is a must.

From the RECA (Real Estate Council of Alberta) specifications: “The RMS allows a tolerance level of 2% of the RMS area for the property. However, every effort must be made to measure the property as accurately as possible.”

I imagine its similar here, but whos going to argue a machine measuring a space compared to manually doing it. I dont know how you could have that much human error with an iguide but I may be wrong. Many realtors still do it manually and i cant see how they arent out by more than 2%

Ive scanned over 300 spaces and no ones ever said anything so either my technique is sufficient or ive just been lucky lol