Do you account for wall thickness?

[HowAboutNo]

The assessor's property cards in my area usually report GBA and GFA as the same figure. The reports I assist my supervisor with also treat the terms synonymously. However, the questions in the AI courses I've taken treat them differently. They stipulate the area occupied by walls, so you can subtract it from GBA and get GFA.

Should we be subtracting wall thickness from GBA when determining GFA, or is this just AI assuming an unrealistic level of info?

If we do account for wall space, how exactly do you measure that accurately? (Assuming it's not new construction, with an engineered blueprint)

Thanks

 

[Terrel L. Shields]

ould we be subtracting wall thickness from GBA when determining GFA, or is this just AI assuming an unrealistic level of info?

Nonsensical. I don't know any appraiser who subtracts the wall thickness. It's a pointless gesture as the difference is usually small anyway. Assessors only measure the outside. I'd rely upon their measurement in lieu of my own measurements and cite the source.

 

[HowAboutNo]

Nonsensical. I don't know any appraiser who subtracts the wall thickness. It's a pointless gesture as the difference is usually small anyway. Assessors only measure the outside. I'd rely upon their measurement in lieu of my own measurements and cite the source.

That's what I was thinking. I wouldn't trust my own measurement over the assessor. But several of the AI HBU course questions include wall area, and expect you to deduct it. I played the game, and passed the course. It seemed unrealistic, but I'm still a trainee, so I could be (often am) wrong.

 

[Long Walk]

Nonsensical. I don't know any appraiser who subtracts the wall thickness. It's a pointless gesture as the difference is usually small anyway. Assessors only measure the outside. I'd rely upon their measurement in lieu of my own measurements and cite the source.

The measurements become an issue in markets or in total leased space where the difference creates a significant difference in rent. Good quality office and retail in more valuable locations are an application where the interior measurement will determine the leasable space. Industrial doesn't care. Assessors in New England measure the exterior dimensions. In all things, the market speaks and we follow it.

 

[Michael P Jacobs MAI]

If your market is predominantly CMU construction like it is here the wall is about 8-9" assuming an 8" block and an inch for drywall.

BOMA standards are interior measurement, but our regional market participants do not follow BOMA standards. Assessor cards and condominium document surveys can be different - some interior, some exterior, and some include common areas and/or even covered walkways. Nobody understands this concept except appraisers, so you have to make the call. Be consistent where you can - if the market is using exterior measurements, say and do that. If you find with sample measurements that a condo survey is using interior measurements do that - although you will never be certain (unless you've measured them before) that condo doc measurements will be consistent between developments.

Most "errors" fall within the rounding range or are not that significant, but $/SqFt differences can be amplified by smaller spaces and this where you have to be most careful.