IRC - Two-Family Residential Corridor Ratings

[drawman]

I am working on a two-family residential unit (existing construction) using the IRC-2018 in PA. The codes are strictly enforced where I am working. One unit is on the first floor, and the second unit is on the second and third floors.

The walls of the existing hallway and stairs are finished with plywood paneling. It's a condition that seems unsafe to me. However, I can't find any language in the residential building codes stating that corridors require any fire rating.

IRC 302.7 requires under-stair protection (the corridor includes a stair). IRC 302.3 states that the units (and their supporting construction) require 1-hour fire separation from each other. PA doesn't require sprinklers in residential construction. I told the clients they should remove all the paneling and replace it with 5/8" Type X GWB, but it’s a considerable effort and expense. They are questioning line and verse. Maybe I argue that all the perimeter walls of the first-floor unit require a 1-hr rating.

Is there anything I am missing? Thoughts?

 

[steveray]

Yep...
R302.3 Two-Family Dwellings
Dwelling units in two-family dwellings shall be separated from each other and from common spaces serving both dwelling units by wall or floor-ceiling assemblies having not less than a 1-hour fire-resistance rating when tested in accordance with ASTM E119, UL 263 or Section 703.3 of the International Building Code.
R302.9.1 Flame Spread Index
Wall and ceiling finishes shall have a flame spread index of not greater than 200.
Exception: Flame spread index requirements for finishes shall not apply to trim defined as picture molds, chair rails, baseboards and handrails; to doors and windows or their frames; or to materials that are less than 1/28 inch (0.91 mm) in thickness cemented to the surface of walls or ceilings if these materials exhibit flame spread index values not greater than those of paper of this thickness cemented to a noncombustible backing.

R302.9.2 Smoke-Developed Index​

Wall and ceiling finishes shall have a smoke-developed index of not greater than 450.

Of course there is nothing that requires them to "upgrade"....but that is a deeper discussion....Welcome to THE Forum.....

 

[drawman]

Interesting. The language was updated in IRC 2021 (compared to IRC 2018.) We don't have a valid OCC permit, so I will argue for the upgrade based on safety, flame reasons, and because the current codes require.

https://up.codes/viewer/pennsylvania/irc-2018/chapter/3/building-planning#R302.3

 

[Mr. Inspector]

If the plywood walls are existing and you are not replacing them there is nothing to do.
Also, the state only requires a permit if you are doing something structure in a one- or two-family house unless the local municipal has amended the PA UCC. What work are you getting the permit for?

 

[drawman]

The client got a stop work order for doing work without a permit.

I was brought in as architect because the property did not have an occupancy permit for a two-family residential unit. I need to submit stamped plans showing compliance with the adopted codes, which in my case is IRC-2018.

 

[BN4537]

So, they currently have occupancy as a single family dwelling? It was not a duplex before?

 

[drawman]

The building does not have a valid occupancy permit, which is not that uncommon for a residential structure. The previous owner went for zoning approval but never completed the C of O requirements for a two family residential structure.

 

[BN4537]

The building does not have a valid occupancy permit, which is not that uncommon for a residential structure.

Was it used as a duplex before?

 

[drawman]

It was used as a duplex but not legally so.

 

[BN4537]

Interesting. The language was updated in IRC 2021 (compared to IRC 2018.) We don't have a valid OCC permit, so I will argue for the upgrade based on safety, flame reasons, and because the current codes require.

The upgrade is certainly a good idea. I don't know if the building department can make you upgrade or not without knowing more specifics.

If you had a legal single-family and wanted to turn it into a duplex, I would definitely add the fire separation. If there was no codes when it was built, then we would probably allow it to continue to be a duplex without upgrading, but it also would depend how far they are going with the renovation. New cabinets and a few fished wires no, moving walls and taking all the drywall down and full MEP replacement, probably.

Probably will also depend how infamous these owner(s) are about not pulling permits and dodging rules too. If they already have a history with the building department, they might be harder to work with.

 

[mtlogcabin]

. I told the clients they should remove all the paneling and replace it with 5/8" Type X GWB, but it’s a considerable effort and expense.

You should be able to put the GWB directly over the paneling.
You can also go to the IBC Section 722.6 to document what you may do to reach the one hour

 

[Mr. Inspector]

If built or changed to a two-family home before 2004 (before the state adopted the ICC codes) a C. O. was not required unless the local municipal had a code before 2004.