Mixed Use

[VERMA071]

Hello Everyone,
I am working on a project and would like to request your opinion. The project is in New jersey and the applicable building codes are
NJ1BC 2018, Rehabilitation subcode NJAC 5:23-6

The required front and side setbacks are 0' and the required rear setback is 20'. The maximum stories allowed are 5 and the max. ht. 60'. The lot is undersized lot.
The existing building is a two story building with basement. There is no way to enter basement directly from front. The person will have to go to second floor via flight of stairs on left and then get down from stairs on the other side to reach the rear yard and go to the basement. The first floor consists of a retail store and a residential unit and the second floor has two residential units. My client is looking to add 1 more story consisting of 2 more apartments. I have a question related to egress requirement. The way existing is built, I will have only one egress stair from the send as well as proposed third floor. Is one means of egress requirement sufficient for 4 apartments on 2nd and 3r floor? Please advise.
Please see attached floor and advise if there is something else I need to keep in mind while working on this project.
Thx,

 

[walker.t]

he applicable building codes are
NJ1BC 2018, Rehabilitation subcode NJAC 5:23-6

Sorry, I can’t comment on that but I’ll share a few thoughts not related to that code.

1. Will you have problems with the width of the egress path from the third floor being reduced as it goes down the new stairs (which will need to meet current codes) to the existing stairs? We start in 1011.2 Width and Capacity which specifies 44” minimum with an exception allowing 36” for an occupant load of less than 50. But 1011.2 references 1009.3 regarding stairs as part of an accessible means of egress, 1009.3.2 requires 48” between handrails unless the building is sprinklered. I’m not seeing an exception for that due to low occupant load.
2. You are going to need to sprinkler the building because of the R-2 (apartments) per 903.2.8 and 420.4, no exceptions. So you need to show provisions on your drawing for your sprinkler riser room and riser running vertically through the building.
3. Check your code for requirements for separation between dwelling units and other dwelling units and other occupancies per 420.2 (Separation Walls) and 420.3 (Horizontal Separation.) Both fire partitions and horizontal assemblies typically require supporting construction to be rated but there are exceptions for Type IIB, IIB, and VB that might apply to your project, see 708.4.1 for fire partitions and 711.2.3 for horizontal assemblies.
4. Are they going to let you use those stairs at the back with the wedge-shaped treads?

Is one means of egress requirement sufficient for 4 apartments on 2nd and 3r floor?

Maybe, look at Table 1006.3.4(1) (Stories With One Exit or Access to One Exit for R-2 Occupancies.) You won’t need an emergency escape and rescue opening per 1030.1 Exception 4 because you’ll have sprinklers. Code may allow that exception, makes me uncomfortable.

 

[Yankee Chronicler]

Sorry, but I'm drawing a blank. UpCodes doesn't seem to include the New Jersey Rehabilitation Code, which is what you use instead of the International Existing Building Code. NJ does adopt the IBC and I would expect that the addition of a third story would require that the addition comply with the IBC for new construction -- but in adopting the IBC New Jersey in its infinite wisdom deleted the definition of "addition," so I don't have any idea where to even begin looking for answers to your question.