Bathroom walls

[Baddhabit]

Can I use plywood rather than gypsum on the exterior walls of a small bathroom in a large shop being used for heavy equipment storage?
The walls will be getting wet occasionally from their pressure washer.

 

[Sifu]

Maybe. Not sure what code you are under or if you are not under any code, but the 2018 IBC excepts toilet rooms not accessible to the public. Code is less than clear about what constitutes "public" but I take public as anybody not in their own personal private space, such as a dwelling or hotel room. That wouldn't apply to a toilet room used by workers IMO. Best to consult with your local AHJ. Otherwise not a good idea for sanitation purposes to put wood or drywall too close to any area subject to splashing.



The IPC defines the terms this way:

 

[ICE]

Can I use plywood rather than gypsum on the exterior walls of a small bathroom in a large shop being used for heavy equipment storage?
The walls will be getting wet occasionally from their pressure washer.

Neither will hold up. FRP will.

 

[steveray]

On the outside?....Should not be a problem...If it is not structural it would be allowed even in "noncombustible" construction.....

 

[Yikes]

Can I use plywood rather than gypsum on the exterior walls of a small bathroom in a large shop being used for heavy equipment storage?
The walls will be getting wet occasionally from their pressure washer.

Welcome to the forum!
If I understand correctly:

1. You have an enclosed large shop.
2. Inside that shop, you are building a freestanding restroom.
3. On the inside face of the restroom walls, you will comply with moisture resistance.
4. On the outside face of the restroom walls - - that is, the face of walls that are exposed to the interior of the rest of the shop - - you are wondering if the wall finish is allowed by code to be plywood.
5. If code does allow it, you are wondering if it is a good idea ("best practice"?) to install plywood as a finish wall surface in an area that might receive direct spray from a pressure washer.

Is this correct?
Do you know the "construction type" of the shop, as listed on any existing permits / certificates of occupancy? For example, is the shop considered by the building department to be noncombustible construction?

 

[Baddhabit]

Thanks for the quick responses! It is a red iron building so my bathroom will be the only combustible part of the entire shop.
It's owned by a city for storing some heavy equipment. They will also have a large pressure washer approx 40 feet from my bathroom.
The bathroom is positioned in a corner of the building, so I'm only putting up two walls. They don't want us spending a bunch of money, but I want to make sure it conforms to code. Plans just mark out the location of the bathroom with no details.

 

[Sifu]

Thanks for the quick responses! It is a red iron building so my bathroom will be the only combustible part of the entire shop.
It's owned by a city for storing some heavy equipment. They will also have a large pressure washer approx 40 feet from my bathroom.
The bathroom is positioned in a corner of the building, so I'm only putting up two walls. They don't want us spending a bunch of money, but I want to make sure it conforms to code. Plans just mark out the location of the bathroom with no details.

Ok, so I think I misunderstood. I assumed the question was about the interior of the exterior walls. The red iron description may hint at the construction type, but does not by itself determine it. Depending on various factors it is likely either IIB or VB. If IIB, things may get more complicated for you. If IIB then combustible construction for interior partitions wouldn't meet code. Metal studs and FRT would though. If VB, use anything you want.

 

[steveray]

You could reasonably call the plywood a finish and use this from 603.1 #7:

1. Interior wall and ceiling finishes installed in accordance with Section 803.