Existing fixed stair to renovated attic ... Can I use the existing 30" stair or do I need to increase width?

[allensamuels]

Here are the details:

This is an existing single story home. There is a 30" fixed stair to the attic. The attic is currently unfinished, but has large areas that meet IRC 305 head height requirements that the owner would like to capture.

The desire is to convert ~500-800SF of the attic to occupiable space. Can the existing 30" width stair serve the converted attic or does it need to be enlarged to meet 36min width?

Is there any wiggle room/advantage to considering this an "habitable attic" vs a "story"? Is it possible that the existing attic is considered "habitable" in it's current state (thus, there is no proposed change in classification -- just adding finishes)?

Any thoughts appreciated! I'm thinking outloud a bit here and probably missing something. I've dug through several threads about attic stairs on the forum and am not clear on my specific case.

Working under 2015 IRC. Thanks in advance.

 

[allensamuels]

Also worth noting that the rise/run is probably not to compliant, but I can't confirm until I check it out next week.

 

[ADAguy]

All interesting questions, best practice if intending to occupy, make it wider with appropriate rise and run. Does attic have windows?

 

[allensamuels]

All interesting questions, best practice if intending to occupy, make it wider with appropriate rise and run. Does attic have windows?

Agree it's definitely the best practice. Increasing the width is likely managable, but rise/run will probably yield a top of stair landing with a ~5-6' ceiling height. Pulling on that thread will start to unravel the ground level layout (if the bottom of stair on level 1 needs to shift around).

There is currently a egress sized window in the attic, which I think helps the argument that the existing space is a habitable attic.

Owner mentioned popping a dormer in, but is trying to avoid for budget reasons. A dormer would also open some questions for me about whether it's a habitbale attic vs. story (a discussion I found on an old post).

 

[Sifu]

As an attic stair I wouldn't worry about it. As a stair to an occupied story or attic I would. It is the difference between a means of egress and NOT a means of egress. R311.4 requires a compliant stair from habitable attics, and that would trigger risers, treads, landing heights etc. The argument as to whether it was designed as a habitable space with a compliant stair at the time of construction could be made, but that would be a tough argument to make.

 

[my250r11]

Might be easier to provide a complaint means of egress with an outside stair.
Or possibly widen to 3 ft and see if they will except rise & run as technically infeasible.

 

[MACV]

The interpretation of the current vs proposed use and whether or not the stair is "existing non-conforming" (grandfathered) is up to the local building official. I've had good success showing building officials dimensioned plans. The 2015 IRC requires a new stair to have a minimum width of 36" above the permitted handrail height but below that height the minimum width is 31 1/2" so the actual configuration and dimensions of the handrails/guards, treads, risers, winders, headroom and landings is important. An approval process should start with a dimensioned drawing.

 

[Paul Sweet]

Has the International Existing Building Code been adopted by your jurisdiction? If not, you might try basing a code modification request to keep the existing tread & riser dimensions on IEBC 1101.4.1 exc. 3.

 

[ADAguy]

Also consider the lack of "functional useability" of maintaining a too narrow stair too.

 

[allensamuels]

Has the International Existing Building Code been adopted by your jurisdiction? If not, you might try basing a code modification request to keep the existing tread & riser dimensions on IEBC 1101.4.1 exc. 3.

Yes, 2003 with local amendments.

 

[allensamuels]

Appreciate all your replies. Next steps for me are to get accurate measurements of stair and updating the existing floor plan drawing to reflect (along with checking out the top of stair landing condition and head height).

From there it's getting a final program from the owner, then going down to talk to the city.

Again, very much appreciate your thoughts and helping me think outloud.

 

[ICE]

Given the funky stairs the logical assumption is that the attic is just an attic. Converting it can happen if it meets code. Proper stairs is paramount. Receptacle spacing, conditioning, insulation, light and ventilation all have to be addressed. Is there proper floor framing?

California Title 24 would probably kill it....but hey now, you are in Texas. We are considering a move to Texas. When my wife came to America she landed in Houston. She doesn’t want to return but Texas will not tax my pension.

 

[ADAguy]

Consider Austin?