Confused - Building Area calculation

[ADAguy]

Nice of "some of you" to share with our "newbie" differences between useable and rentable square footage.
Many building departments base permit fees on net useable (minus columns and other non-occupiable spaces (vent and duct shafts) vs gross area.

It becomes a bit more complicated when the reflected ceiling is larger than the floor plate due to outward leaning walls (think upside down pyramid) (this can wracks havic with mechanical calcs.).

 

[Yikes]

People don't stand within walls... unless of course they work for BOMA apparently. LOL

As an aside, I recently heard a history podcast about Assyrian king Ashurnasirpal II. He bragged about walling his enemies in alive, inside a masonry wall. the term is known as immurement, (from Latin im- "in" and mūrus "wall"; literally "walling in").

 

[Paul Sweet]

The only time I've seen areas measured to the inside face of exterior walls is for code area calculations. Zoning wants to see the full physical size of the building, not just the occupiable part. Cost estimates include wall area, which isn't free. I expect that most people just go ahead and use the area to the outside face of the walls on their building permit application, unless the building is on the borderline for area limits.

 

[Yikes]

Paul, the first sheet of our architectrue firm's building plans always have at least TWO calculations:
1. Are per zoning code
2. Area per building code/fire code

This is especially important if the project has a parking structure, because many zoning codes do not count parking structure area in their allowable Floor Area Ratio (FAR). In that situation difference between zoning vs building area calculations can be very significant.
It is worth it to post both numbers. Our plans are intended not only to secure permit for the current project, but the also serve as a record for future reference. When the client wants to add more floor area to their site in the future, the planning department knows which number to examine on our record drawings for FAR.

We may also have additional area numbers such as BOMA for investors and tenants, conditioned space for energy calculations, building footprint for planning and landscape calcs, pervious vs. impervious surface for stormwater calcs, etc.

 

[RANDOM]

Paul, the first sheet of our architectrue firm's building plans always have at least TWO calculations:
1. Are per zoning code
2. Area per building code/fire code

This is especially important if the project has a parking structure, because many zoning codes do not count parking structure area in their allowable Floor Area Ratio (FAR). In that situation difference between zoning vs building area calculations can be very significant.
It is worth it to post both numbers. Our plans are intended not only to secure permit for the current project, but the also serve as a record for future reference. When the client wants to add more floor area to their site in the future, the planning department knows which number to examine on our record drawings for FAR.

We may also have additional area numbers such as BOMA for investors and tenants, conditioned space for energy calculations, building footprint for planning and landscape calcs, pervious vs. impervious surface for stormwater calcs, etc.

Do you include RFA in your title sheet. I typically do.

 

[ADAguy]

Not confused enough?

However, the "bearing" weight of a building is inclusive of the out to out (exterior to exterior) size of a building which determines the compressive loading on the footings and soil beneath.
The out to out may also impact determination of FAR (Floor Area Ratio) vs allowable lot coverage.
Habitable area could be seen as occupiable area for tax accessors purposes.
A porte Cochere is a pass thru structure not intended for overnight parking or storage, unless as some do, it has a floor above it which should then be included in the calculations.