Definition of floor area..... what is it?

[dshall]

Hi all,  what is the definition floor area......  for minimum setbacks and FAR calculations etc.

 

Do you measure to interior face of stud wall for area (edge of foundation)?

Do you measure to exterior face of stud wall for area?

Do you included the exterior finish for area?

Do you include 2nd floor stairwells?

 

When determining setbacks do you.....

Do you dimension to exterior face of stud wall (the foundation)

Do you dimension to the exterior face of finish?

 

What about required 1-hour walls?  Less that 5' to property line it needs to be one-hour.....  but do you measure to the exterior face of finish or to the exterior face of studs?

 

I am relatively new to the business (since 1974) so I am still learning,  please help me.....  

 

 

[dshall]

FYI. 

 

 

[DRAWZILLA]

i have been going to the outside of the stud wall-no finish, and have been forever, the cities seem to allow it.

[dshall]

1 minute ago, DRAWZILLA said:

i have been going to the outside of the stud wall and have been forever, the cities seem to allow it.

 

Yeah,  that is what I have always done,  but now I am finding some of the cities.... Solana Beach,  Coronado,  maybe Encinitas are using the exterior finish.

 

This is driving me nuts.  I wish Michael would come up with a SUPER MACRO that would adjust the floor area depending on which jurisdiction I am working in.

 

Hey Michael,  winter is coming,  the snow will be falling,  you will be stuck in your house with nothing to do,  please work on this,  thanks.

[dshall]

This is the latest.....  I am adding more floor area to an existing house,  if I double the floor area on the project I have to use all electric,  no gas ranges,  so I need to keep the new floor area under the existing floor area so I can use a gas range. (remember we have a climate crises and if I use this electric range vs gas I will save the world).  

 

So how do I figure the new and existing floor areas according to the jurisdiction?   Well it is obvious,  you measure to the exterior face of existing studs at existing first floor but for the new 2nd floor addition you measure to the interior face of new studs at 2nd floor. (it's obvious.....  right?). and then you do not include the new stairwell area at 2nd floor.  I kept the new floor area under 100% of existing floor area by 6.387 s.f.

 

My client can have a gas range and the world is saved and I can sleep at night!  

 

Ain't life grand?

[javatom]

The ever present decision of including the stairwell or not in the square footage.  I usually include it.  It is a great tool to use when you are trying to show less total square footage to a building department.  I include it to show clients a more realistic statistic of what they are about to build.

[GeneDavis]

Isn't it a "standard" in the real estate biz to count the stairs once?  Thus a simple staircase 3 wide x 12 long is 36 sf attributed to the floor on which it lands (starts "up"), and zero on the floor to which it ascends.

 

So what do you have when a finished basement is accessed by a stairs directly under the one going from 1 to 2?  Does that basement include the 36 sf or not?  I think it does.

 

My logic is that the stairs, the treads upon which one walks, is habitable space and should be counted, but only once for each run of stairs.  Stacked stairs in my example are 36 plus 36.  But only that.  Where you put the footage, which floor, is up to you?  Or does the "standard" say?

 

As for Scott's dilemma, one can sort of understand a building jurisdiction wanting to have numbers that are verifiable by field measurements, taken from the outside of the house, thus the inclusion of finish.

 

Hey Scott!  Draw up a suggestion that allows one to set this all up in preferences or somewhere.

[DRAWZILLA]

2 hours ago, dshall said:

This is the latest.....  I am adding more floor area to an existing house,  if I double the floor area on the project I have to use all electric,  no gas ranges,  so I need to keep the new floor area under the existing floor area so I can use a gas range. (remember we have a climate crises and if I use this electric range vs gas I will save the world).  

 

So how do I figure the new and existing floor areas according to the jurisdiction?   Well it is obvious,  you measure to the exterior face of existing studs at existing first floor but for the new 2nd floor addition you measure to the interior face of new studs at 2nd floor. (it's obvious.....  right?). and then you do not include the new stairwell area at 2nd floor.  I kept the new floor area under 100% of existing floor area by 6.387 s.f.

 

My client can have a gas range and the world is saved and I can sleep at night!  

 

Ain't life grand?

that's a new one for me so far, hope it never happens around here

[richoffan]

Many states have passed legislation to squash this ridiculousness. I guess the gas / oil - appliance lobby is stronger there. Try Colorado where you can't have a wood burning fireplace unless it conforms to unrealistic restrictions (EPA Phase II emissions - essentially a wood burning stove) or you are over a certain elevation, unless of course it's an exterior fireplace in which case anything goes. I've found it best to ask because the AHJ determination is SO different across the country. FAR for stairs, open below, 2.5 story foyers, porches with full foundations, interior balconies, elevator shafts, fireplaces...and impervious surface? Try getting a ruling on large pavers with grass between. Setbacks usually run to the foundation but with super insulated walls running 5 inches + past the foundation I've been surprised before even with Roxul, treated furring and thin stone veneer! I've worked on old (really old) structures where the mud sill overhangs by 2" to square up a frame over a crooked foundation. Oh and bay windows? 3 foot plus overhangs on prairie style? .....

[lbuttery]

this topic arose many times since I joined in 2006

 

there are many "standards" depending on who (which industry) the calcs are needed for

 

I have recommended to CA that Chief create a spreadsheet with the most common "standards"

then we could use the most relevant for whatever client is asking

 

search for the prior threads

is the old forum still available for searching ?

 

Lew

[dshall]

BTW,  we count stairs twice out here.  Basement stairs once.

 

If you consider exterior finishes for FAR,  do you include finishes for COVERAGE?

 

rhetorical questions.
 

 

[Joe_Carrick]

2 hours ago, dshall said:

BTW,  we count stairs twice out here.  Basement stairs once.

 

If you consider exterior finishes for FAR,  do you include finishes for COVERAGE?

 

rhetorical questions.
 

 

Scott,

 

I count stairs only for the floors on which they land at the bottom.  IOW, the top floor which is only a stairwell doesn't count - it's just a hole in the floor.

 

Another way to look at it is: "Tread and Landing" areas are only counted once.

 

Elevators are only counted once.  Doesn't matter which level it's stopped at, all other levels are just holes in the floor.  

[dshall]

2 minutes ago, Joe_Carrick said:

Scott,

 

I count stairs only for the floors on which they land at the bottom.  IOW, the top floor which is only a stairwell doesn't count - it's just a hole in the floor.

 

Another way to look at it is: "Tread and Landing" areas are only counted once.

 

For computing FAR,  the stairs are counted twice.  

 

Whenever the ceiling height is greater than 15',  the area is counted twice with the understanding it is possible to add a floor into that area.

 

Isn't that interesting.....  2 experienced users have different understanding on how to tabulate floor areas.  That is the purpose of this thread.

 

I am dealing with a project in Coronado right now and we are trying to get ever s.f. of area we can so it is very important to understand what is floor area.

 

It feels like I am always walking in a field of land mines.... if I do not get things dialed in just right,   the next step will blow up the entire project.

 

[Joe_Carrick]

Scott,

 

I understand that some cities - San Diego for example - have such rules for the FAR calculations.  That's not the same as "Living Area" which is used for Real Estate purposes.

 

I had a project in the "Bird-Rock / La Jolla" area of San Diego where there was a high ceiling area which the city counted for the FAR.

 

OTOH, as far as I know San Diego County doesn't count such areas.

[DRAWZILLA]

what really matters is that I add all the square footages for my square footage price. For the cities, it might differ from that depending on the city, I usually have to check with them. 50 different cities are too much especially when they change constantly and often, even amongst different plan checkers in the same city