I think some of these answers have muddied the waters, especially concerning the need for a second stair, which is not a requirement in a single family home. I'm assuming that there is no stair to the current attic. I believe you are correct in that any new stair must meet the code for new construction. Any new stair cannot make the existing means of egress any more non-conforming than they already are. So if the new stair creates a headroom problem that makes the existing stair more non-conforming it would not be allowed. My
opinion is that the issue of the reduction in egress width would be acceptable because you are making all new areas meet the code. That does not prevent you from being able to pass through a non-conforming space on your way from the new space. Unfortunately this is one of any number of scenarios that are not clearly spelled out in the code.
I assume you do not already have a stair to the attic. If you do it would not have to be updated if there is any type of
legal (i.e. built with a building permit) living space in the attic already. In other words, if there is already a finished space up there the existing stair is okay e
ven if you are adding new construction, such as a shed dormer. If there is no legal living space up there, even an existing non-conforming stair would have to be updated.
Although it is within the building inspector's right to wait for the full set of drawings (at least one way of reading IRC R104), he/she is certainly doing you and your customer a disservice. He/she is the only person who can make such an interpretation. You have the right to appeal their interpretation, but no matter what you or I think about it, their interpretation is what matters (unless appealed). I've never had a building inspector refuse such a question when
adequate design level drawings that fully illustrate the issue are presented.
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John Crowell
Deer Hill Architects, LLC
Peabody MA
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Original Message:
Sent: 08-20-2020 17:36
From: Bruce Ward
Subject: Single Family Residence Addition
Would it be possible to make the new stair longer than the existing one? If there is not enough space between walls, perhaps a winder or square landing at the bottom with another riser or two?
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Bruce Ward AIA
Proprietor
Bruce Ward Architect
Hamilton NY
Original Message:
Sent: 08-19-2020 20:27
From: Paul Levine
Subject: Single Family Residence Addition
I am working with a client who wants to add a 3rd floor to their existing 2 story single family home. The new 3rd floor will be a bedroom and bath. I have a question regarding the stairs. The existing stair, from the first floor to the second floor, does not meet the 2015 IRBC requirements for the stair width (less than 36") and the tread depth (less than 10"). Because the new stair, from the 2nd floor to the 3rd floor, needs to be above the lower stair, the new stair can not meet the the code requirements without compromising the headroom on the stair below.
My question is, has anybody had to deal with this situation and how was it handled? Is there an exception in the code that allows the new stair to be equivalent to the existing stair? If the new stair were to meet code then the exit path would be constricted once to get to the existing stair. My jurisdiction will not provide a code consultation unless we apply for a permit and the Clients don't want to proceed with construction drawings if it will be denied. Appreciate your expertise.
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Paul Levine AIA
Paul J. Levine, Architect
Pittsburgh PA
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