# attic or story?



## barlovian (Nov 20, 2009)

Have you  figured out yet how to differentiate a habitable attic from a story?

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.

ATTIC, HABITABLE. A finished or unfinished area, not considered a story , complying with all of the following requirements:

1.	The occupiable floor area is at least 70 square feet (17 m2), in accordance with Section R304,

2.	The occupiable floor area has a ceiling height in accordance with Section R305, and

3.	The occupiable space is enclosed by the roof assembly above, knee walls (if applicable) on the sides and the floor-ceiling assembly below.


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## jar546 (Nov 20, 2009)

Re: attic or story?

Interesting now we can also discuss the requirements for stairways to attic!  That should ***** the posts :twisted:


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## kilitact (Nov 20, 2009)

Re: attic or story?

barlovin wrote:



> Have you figured out yet how to differentiate a habitable attic from a story?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.
> 
> ATTIC, HABITABLE. A finished or unfinished area, not considered a story , complying with all of the following requirements:
> 
> ...


Are you making the statement that a habitable attic doesn’t need to meet any of the other requirements for habitable space, which would include, among other requirements, the requirement for a code complaint stairway? Or are you saying that it just needs to meet the requirements you have listed, which didn’t include a stairway among other items.


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## barlovian (Nov 20, 2009)

Re: attic or story?

Ouch, sorry, I didn't mean to touch on a sore subject.

I wanted to ask about specific habitable attics, the ones with fixed stairs that are used as conditioned living space such as sleeping rooms, dens, and specific nonhabitable (but still necessary) related spaces such as bathrooms and corridors.

I asked because I was wondering what this is going to do to the prescriptive framing requirements.  Tables for beams and headers, cantilevered walls, and wind bracing refer to stories.

And the limit for roof trusses, R802.10.2.1 Applicability limits.

The provisions of this section shall control the design of truss roof framing when snow controls for buildings not greater than 60 feet in length perpendicular to the joist, rafter or truss span, not greater than 36 feet in width parallel to the joist, rafter or truss span, not greater than two stories in height with each story not greater than 10 feet high.

These are just few examples.    I haven't found any restriction yet that would prevent a habitable attic from having an attic.


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## JBI (Nov 20, 2009)

Re: attic or story?

barlovian - No.

I'm still trying to figure out why we are allowing three story woodframe (type V*b*) residential structures...

Oh yeah, because we no longer assign 'construction type' to Res Code buildings and because of a really badly written interpretation of the Res Code regarding basements that ignores the clear and unambiguous language of the code...   :x

Sorry, rant now over...


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## rktect 1 (Nov 20, 2009)

Re: attic or story?

I am not certain I am following you.  Where is the problem at?

Not only would the attic need to follow those requirements but our ordinances kick in.  The main one being that no residence can be more than 2 1/2 stories AND no taller than 35 feet.  A half story is that portion of a building under the roof, the wall plates of which on at least two opposite exterior walls are not more than four and one half feet above the finished floor of such story.


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## rktect 1 (Nov 20, 2009)

Re: attic or story?



			
				barlovian said:
			
		

> Ouch, sorry, I didn't mean to touch on a sore subject.   I wanted to ask about specific habitable attics, the ones with fixed stairs that are used as conditioned living space such as sleeping rooms, dens, and specific nonhabitable (but still necessary) related spaces such as bathrooms and corridors.
> 
> I asked because I was wondering what this is going to do to the prescriptive framing requirements.  Tables for beams and headers, cantilevered walls, and wind bracing refer to stories.
> 
> ...


Seems like you need a Design Professional.  Prescriptive only goes so far.


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## kilitact (Nov 20, 2009)

Re: attic or story?

barlovian wrote;

A habitable attic can have an attic, and this attic could have stairs that don't comply with R311.5.  :lol:


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## smeismer (Nov 20, 2009)

Re: attic or story?

I believe that the allowance of a habitable attic is to de-facto allow 4 stories under the IRC.  Perhaps the justification is that the code now requires fire sprinklers, so the traditional restriction of egress windows to be below the fourth floor is no longer important (ladders haven't gotten longer, but the opportunity to exit is increased).  The design difficulties associated with wood movement are still there, but there is a good body of example designs, as I believe Washington has allowed this for some time, and Simpson recently tested a five story wood structure for seismic restraint.  Past codes have allowed sloped ceilings, etc.  so I see no other purpose for this inclusion.


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