AskCodeMan

Hi Jerry

I did an inspection yesterday on an "investment home" that was "Completley remodeled".
The Master bath tub stall was drywall right down to the tub and there was no tile on the inside of the full bath shower stall window. I called both as being improper. Suffice it to say this was Curly, Larry and Moe workmanship with Moe leaving early most days.

My problem is in looking up in the residential code R307.2 it only refers to stalls with a shower riser as needing water proof materials a minimum of 6" up the walls. Is there another section I'm missing or is the "Great Code" remiss in not addressing this set-up. Right now I feel I couldn't back up my statement about the tub stall.

I know you can't use water resistant drywall in a shower / tub stall so I can't imagine it not addressing this tub stall with no shower riser set-up. Thanks for your time.

If there is a shower head at the tub (and for a shower stall) the minimum height of the impervious wall covering is 6 feet above the floor, and I would measure that 6 feet from "the floor" of the tub or shower, not 'the floor' outside the tub or shower as that is not what matters, it is about the shower area, not the area outside the shower.

From the 2010 FBC-Residential: (bold and underlining are mine)
- R307.2 Bathtub and shower spaces.
- - Bathtub and shower floors and walls above bathtubs with installed shower heads and in shower compartments shall be finished with a nonabsorbent surface. Such wall surfaces shall extend to a height of not less than 6 feet (1829 mm) above the floor.

If there is a window and the window falls within that 6 feet height, then the wall area around (top, bottom, both sides) the wall area opening to the window also needs to be of impervious material to a minimum height of 6 feet above the tub/shower floor.

Hi Jerry,

The question is about a tub surround that has no shower riser.
Does the code allow the inside of the tub surround to be unprotected drywall right down to the top of the tub?
That section of the code appears to not address it specifically and therefore by default allow it.

bigdog wrote:The question is about a tub surround that has no shower riser.
Does the code allow the inside of the tub surround to be unprotected drywall right down to the top of the tub?
That section of the code appears to not address it specifically and therefore by default allow it.

My error, I thought you mentioned a shower riser at the tub ... the code does not address the walls around a tub without a shower - the code only addresses tub surround walls when the tub has a shower.

Yes, one could have regular drywall, not even painted, down to the tub.

OMG!!
Evidently these wise men who "perfected" the code didn't have children!!
Thanks Jerry
David

David,

I will expand on my "Yes, one could have regular drywall, not even painted, down to the tub." comment with this:
- R702.3.8 Water-resistant gypsum backing board.
- - Gypsum board used as the base or backer for adhesive application of ceramic tile or other required nonabsorbent finish material shall conform to ASTM C 1396, C 1178 or C1278. Use of water-resistant gypsum backing board shall be permitted on ceilings where framing spacing does not exceed 12 inches (305 mm) on center for 1/2-inch-thick (12.7 mm) or 16 inches (406 mm) for 5/8-inch-thick (16 mm) gypsum board. Water-resistant gypsum board shall not be installed over a Class I or II vapor retarder in a shower or tub compartment. Cut or exposed edges, including those at wall intersections, shall be sealed as recommended by the manufacturer.
- - - R702.3.8.1 Limitations.
- - - - Water resistant gypsum backing board shall not be used where there will be direct exposure to water, or in areas subject to continuous high humidity.

You could install that regular drywall down to the tub ... unless ... unless you were to install "ceramic tile or other required nonabsorbent finish material" on the drywall, in which case the drywall would need to be water-resistant drywall ('MR', 'green board', etc).

While it may sound strange that the drywall does not need to be water-resistant until there tile or similar is installed on the drywall as the tile or similar helps protect the drywall from water/moisture damage; however, if there is no water/moisture then there is no need for the tile or similar material to be installed over the drywall, thus the drywall needs no protection.

Here is the potential problem when using regular drywall around a tub: The house is constructed (or bathroom remodeled) with regular drywall down to the tub, the work is complete, the occupant goes to a Big Box store and buys some tile and adhesive - oops ... wait a minute now ... they are not allowed to install that tile they just purchased over that regular drywall - who is going to educate those DIYselfers of all the things they are not allowed to do by the code?

Next problem is this: The house is sold and those 'really nice folks' installed that tile all the way to the ceiling to make the bathroom look really nice ... and no one has any idea that behind the tile is regular drywall, not water-resistant drywall.

Remember, though, the code is "minimum" and does not attempt to regulate common sense, stupidity, unlicensed contractors, or even licensed contractors, who do not know or do not care.

R702.3.8.1 is the code section which does not all even water-resistant drywall to be used as a tile backer board when there is a shower at the tub or in a shower stall, cementitious board is what should be used in those locations.