R202 Definitions

[peach]

Anyone else have an issue with the definition of "attic, habitable"? Particularly since the 2009 IRC says its NOT a story?

Some zoning definitions specially call it a story.

How do you handle?

 

[Yankee]

Fortunately my zoning simply refers to overall height, not stories.

 

[peach]

Here, it depends on the residential zoning classification... but the zoning code looks at "stories" as habitable space from the uppermost "story" to the underside of the roof.. so it can be an issue. We're looking at adding a clarification at the beginning of the IRC that everything is subject to the zoning code..

 

[RJJ]

To answer the question Yes! The definitions helps, but at the same time muddies the water. For me zoning is first, and I believe between S&D and zoning I fixed this issue years ago. I need to go back and read what I had fixed. Must be getting old!

 

[Mac]

R201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter.

I believe the R201 definitions apply only to the "purposes of this code..." Local zoning (or other regs) can have thier own definition, which may differ some. The two don't always agree, nor do they need to.

Peach could consider proposing a change in the local definition to clarify the difference (or similarity) between the two. Too bad we can't change the IRC - or other codes' - definitions.

 

[north star]

* *

Mac,



Your AHJ CAN change [ amend ] the IRC to their own needs.

* *

 

[jim baird]

Still on the '06 here, which doesn't address "habitable" attic.

Could someone post what peach is questioning?

I'm told the "mansard" roof style was invented to skirt some kind of definition.

 

[Mac]

"Your AHJ CAN change [ amend ] the IRC to their own needs."

Maybe you can, but in New York, it's a statewide adoption. It works out better for us because it's administered by the state, too.

 

[Yankee]

Attic, Habitable. A finished or unfinished area , not considered a story,complying with all the following requirements:

1. the occupiable floor area is at least 70 sf per R304

2. the occupiable floor area has a ceiling height in accordance of R305

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

wish I had teh commentary as to why it is not to be considered a story.

 

[jim baird]

Thanks, yank.

"finished or unfinished"

Is that another threshold crossed?

 

[Yankee]

I think the point being, if it is a readily accessible space (with stairs and enough room), then the "bones" should be in compliance with living space as all that it would take is some interior finishing. I thought it was going to be a big problem, but then I realized that I already require the bones to comply (stair dimensions and EERO), unless access is a pull down stair or less. . . . just the way I have been doing it. Yes, Brudgers, I am expecting your comment.

 

[peach]

The "habitable" attic will require a code compliant stairway... and an egress window.. and a smoke detector.. whether it's a finished space or not.

You're actually also looking at a potential (essentially) 5 story house (basement, 3 stories and this attic)... of course, you'll also see a residential fire sprinkler installed.

Even with zoning restrictions, the designer may rely on the IRC (only to get shot out of the water).

 

[liarchitect]

be careful, if it is considered a story, residential fire sprinklers will be required anything 3 stories or more

how is the access be provided to the space? do you have adequate egress windows?

is it insulated?

 

[smeismer]

I believe that the "habitable attic" definition was placed in the code solely to allow 4 story residences without changing the scope statement in R-101.2 as that would have required a change to the IBC. I question whether the egress window is of much value, as egress window requirements in the past have always specified "below the fourth floor" due to ladder lengths. Sprinklering may help there. The vertical movement of tall wood framed buildings has always been of concern, and still is in the IBC (2304.3.3 in the 2009), but the IRC, being more prescriptive, seems to ignore this. I understand that Washington State has had some success with tall wood buildings, but it still seems that the "habitable attic" creates more problems than it solves.

 

[Yankee]

The "habitable" attic will require a code compliant stairway... and an egress window.. and a smoke detector.. whether it's a finished space or not.You're actually also looking at a potential (essentially) 5 story house (basement, 3 stories and this attic)... of course, you'll also see a residential fire sprinkler installed.

Even with zoning restrictions, the designer may rely on the IRC (only to get shot out of the water).

The basement would be considered a story, wouldn't it? So Three stories if there was a basement and a habitable attic would most often (in my area) be two stories above grade with exterior walls on all sides, and the attic. That is pretty much what I have here already. Granted, if there were no basement (say if it were a crawlspace . . . . )

 

[georgia plans exam]

The IRC applies to stories "above grade."

IBC Table 503's height and story limitations apply to "above grade."

Sprinkler increase applies to stories "above grade."

I don't believe basements count.

GPE

 

[Yankee]

The IRC applies to stories "above grade."IBC Table 503's height and story limitations apply to "above grade."

Sprinkler increase applies to stories "above grade."

I don't believe basements count.

GPE

Beg to differ, what the IRC covers does not mention if the storiess are above or below grade. It simply says "not more than three stories in height"

EDIT!! -- now isn't that interesting, the Section R101 does in fact say above grade, I was reading off of the Sample Ordiance for adoption , , gee, , someone better change that! And besides that, I should have known better!

 

[peach]

depends on the grading for the basement... I could design a walkout basement with 2 bedrooms (with egress wells), that's still 51% below grade... it could be essentially a 5 story structure.