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The Custom Residential Architects Network (CRAN®) Knowledge Community develops knowledge and information to benefit architects who are engaged in, or who are interested in learning more about, custom residential practice. CRAN® presents information and facilitates the exchange of knowledge and expertise to promote the professional development of its  members via discussion forums, national symposia and conventions, publications, and local activities.

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Single Family Residence Addition

  • 1.  Single Family Residence Addition

    Posted 08-19-2020 20:28
    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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  • 2.  RE: Single Family Residence Addition

    Posted 08-20-2020 17:49
    Paul,

    I have never heard of being allowed to add a non-compliant stair above and existing non-compliant stair.  It's just my opinion, but I doubt your jurisdiction would allow it.

    I don't know anything about your proposed floor plan.  But, it seems a pretty easy thing to add a wider stair above a narrower stair.  The framing of the stair hole width above does not need to coincide with the stair hole width below.  You just have to correctly carry the loads of the headers at each end.

    Additionally, if you raise your starting landing and make it the first riser, or if you turn the last riser at the top, you might gain just enough room for the compliant length of the stair run.  That would also help with the headroom of the lower stair.  I say this without knowing your floor plan.

    Best of luck to you.

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    Robert Braddock AIA
    Principal
    Red House Architects, PLLC
    Arlington VA
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  • 3.  RE: Single Family Residence Addition

    Posted 08-20-2020 17:50
    The existing stair would need to be rebuilt so it complies with the current code. You cannot send occupants from a complying stair to a non-complying stair in an exiting system.

    Donald Henke AIA

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    Donald Henke AIA
    Design Manager
    Turner Construction Company
    Dallas TX
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  • 4.  RE: Single Family Residence Addition

    Posted 08-20-2020 18:53
    I have run into this situation, and similar ones, more than once.  Where I practice, there is nothing to be done but to either find a different location for the new stair, or go ahead and reconfigure the existing stair to code before adding the new stair.  It's always a challenge, but that kind of challenge happens to be a part of the job I enjoy.  What did they used to say in school -- something along the lines of "limitations are opportunities for creativity", or something along those lines?  Good luck to you.  I hope you enjoy the exercise in creativity!

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    Mollie Ackner AIA
    Principal
    SoliDeo Design Studio
    Durham NC
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  • 5.  RE: Single Family Residence Addition

    Posted 08-21-2020 18:40
    Sometimes you can get a "Code Modification" approved with your AHJ that would allow a stair that does not meet code when it is an addition to an existing structure, but they typically want you to provide some sort of compliance alternative (additional egress, additional/enhanced detectors, ect). You should also check with the permit officials about the existing stair--In my experience if you add new habitable space above an existing stair (especially a bedroom) they may require the old stair to comply with current code or get a code mod-depending on the existing building code determination. Often a quick concept sketch with dimensions will suffice for this.

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    William Cawood AIA
    Principal
    Cawood Architecture, PLLC
    Purcellville VA
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  • 6.  RE: Single Family Residence Addition

    Posted 08-24-2020 13:43
      |   view attached
    Thanks to Everyone,

    I received a lot of interesting responses and appreciate everyone's thoughts.  Proposing a compliance alternative such as an additional egress path or fire escape and enhanced detectors is a really good idea and most likely the best way to proceed.   I attached my schematic design sketch for reference.  The house is very small and any modification to the existing stair or surrounding spaces compromises the rooms to the extent that there's no advantage in adding an additional room, because they would lose one on the lower floor.

    The local building department is very frustrating.  They will not provide preliminary code interpretations - they consider this a code consultation or advise as opposed to an interpretation.

    Thanks.


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    Paul Levine AIA
    Owner
    Paul J. Levine, Architect
    Pittsburgh PA
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  • 7.  RE: Single Family Residence Addition

    Posted 08-24-2020 18:14
    Join the ICC and get their code interpetation

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    Henry Thompson AIA
    Member
    H.B. Thompson Group llc
    Freehold NJ
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