2015 IRC Permanent Attic Stairs

[George Gordon]

Hi All,

We would like your insight on permanent attic stairs under the 2015 IRC. Is there anything in this code that prohibits permanent stairs to a non-habitable attic from being narrow (30") and steeper than code compliant stairs? Obviously we can install pull-down stairs/ladder, but we would like a more finished solution.

Looking forward to receiving your thoughts!

 

[steveray]

Get a modification or approval to use a ships ladder if you need to? Just mechanicals up there?

 

[George Gordon]

I was just about to edit my post and suggest that it be classified as a ships ladder! So next question, what makes steep (non code compliant) stairs become a ships ladder? The deletion of riser boards?

The 2015 IRC seems to allow for ships ladders. Does this require additional approvals?

 

[Paul Sweet]

A ships ladder typically has a slope over 70 deg. (OSHA bans stairs between 50 deg. and 70 deg. slope, although that doesn't apply to residential). IBC 1011.15 has dimensions for a ships ladder.

 

[George Gordon]

Working from the 2015 IRC, R.311.7.12, if our "stairs" have: (1) a total tread depth plus nosing of not less than 8.5", (2) a riser height of not more than 9.5", and (3) handrails on both sides, then such "stairs" could be classified as a ships ladder. Is this other members' interpretations as well?

 

[Mr. Inspector]

As a plan reviewer I would approve. If attic is not conditioned a door would have to be on the bottom of the stairway.

 

[Sifu]

I am of the opinion that a stair carries an expectation that a ladder does not. When I use a ladder I pay more attention to foot placement and hand holds. When I use a stair I don't pay as much attention because my body is more accustomed to the act and able to anticipate the movements needed with less conscious thought. But, width isn't really part of that process for me unless I have to turn sideways to use it. From a code perspective I think if a stair is provided it must function like a stair. If a ladder is provided then it does not have to function as a stair. JMHO.

 

[Glenn]

311 in 2021 IRC makes it clear that stairways to nonhabitable attics do not need to comply with 311. That means they do not have to comply with
conventional stairs, spiral stairs, ships ladders, or ATD. This was heavily discussed for 2021. There were NO proposals to change it in 2024.

I do believe that section does need work in regard to deck and porches.

 

[Sifu]

311 in 2021 IRC makes it clear that stairways to nonhabitable attics do not need to comply with 311. That means they do not have to comply with
conventional stairs, spiral stairs, ships ladders, or ATD. This was heavily discussed for 2021. There were NO proposals to change it in 2024.

I do believe that section does need work in regard to deck and porches.

Good to know. Clears up that issue.