Two Story Structure 1

[msquared48]

By code what is the deciding fact on whether or not a structure is two stories, nacessitating the use of an 8" wide stem wall with a larger footing?

I have a standard house with an 8 foot plate height and a 6:12 roof pitch where the owner wants to make the upstairs liveable. I think this occupancy use issue drives the 8" wall.

Mike McCann, PE, SE (WA)

 

[BAretired]

Perhaps it depends on the code you are using, but wouldn't a two story building be one which has two levels or tiers, excluding basement?

BA

 

[csteve]

If you're using the ICC codes you can look up the definition of a story, stories above grade, and a bunch of foundation requirements on the ICC public e-code page. Just search the web for publicecodes.cyberregs.com

 

[DBronson]

Mike:

The 2012 IRC definition of a story is:

STORY. That portion of a building included between the upper surface of a floor and the upper surface of the floor or roof next above (also see "Basement," "Building height," "Grade plane" and "Mezzanine"). It is measured as the vertical distance from top to top of two successive tiers of beams or finished floor surfaces and, for the topmost story, from the top of the floor finish to the top of the ceiling joists or, where there is not a ceiling, to the top of the roof rafters.

The attic would be considered a story. I'd double check to verify that Washington state's definition is the same.

Regards,

DB

 

[XR250]

Could you just design the foundation based on demand rather than prescriptively?

 

[BUGGAR]

I successfully did as XR250 suggests for a number of houses in WA.

 

[msquared48]

XR250:

What do you mean, "by demand"?

Mike McCann, PE, SE (WA)

 

[XR250]

Engineer it based on code mandated design loads (and presumptive soil bearing capacity). I imagine you can get a 4" foundation wall to work fine.

 

[jayrod12]

Around here we call those 1/2 or 3/4 storeys. but they are still noted as storeys. However, we also never go less than 8" for a foundation wall (most of the time we have full basements here).

 

[XR250]

I guess 4" would be a little sketchy for a basement but probably still doable if you had to if there was enough control over rebar placement and not too much backfill