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Discontinuous Gyp. Bd. at shower pan at fire partition

N

nealderidder

Sawhorse
Joined
Dec 7, 2010
Messages
394
Location
Sacramento, CA
R-2 construction, 2009 IBC. I've got shower pans that abut corridor walls and party walls (1/2 hr partitions) in a three story apartment building. The plans call for the assembly to be continuous all the way to the floor and an additional layer of 1/2" green board be added at the shower enclosure to overlap the shower pan flange and provide a flush surface for the shower walls (swanstone type stuff).You know where I'm going already... builder wants to know if there is a way to keep that assembly intact without the additional layer of 1/2" gyp. I'm sure this has been seen by many of you before, know of any clever way to keep assembly intact without the additional Gyp.? View attachment 1183

View attachment 1634

View attachment 1634

/monthly_2012_01/shower.jpg.efb8a4556abeda9ffad5b65da6fd3044.jpg
 
Since it is a fire partition around a residential unit, can they get all of the rating requirements with gyp board on the side away from the shower? Still might have to add a layer, but the shower would remain intact.
 
Many of the units are mirrored at the party wall so the same situation occurs on the opposite side of the party wall...

iggentleman said:
Since it is a fire partition around a residential unit, can they get all of the rating requirements with gyp board on the side away from the shower? Still might have to add a layer, but the shower would remain intact.
Click to expand...
 
Green board (or more appropriately, moisture-resistant gypsum board) is not required behind showers, and is not permitted when the showers have tile installed over the board--only glass-mat water-resistant gypsum board or cementitious tile backing panels are permitted.

If you want some level of water-resistance behind the shower walls, you can get water-resistive Type X panels that will provide the fire-resistance and water-resistance characteristics in a single panel, thus eliminating the two layer application. However, the panel must continue to the floor to provide the required fire-resistive assembly.
 
Couple of years ago I designed a hotel with cement backer board over rated gyp board at the bathrooms that had fire partition walls. The contractor framed it without room for both boards. I went to the maker of the backer board and found that they had 1 hour tested assemblies with their board and fire batt insulation but no gyp board.
 
If they install an NFPA 13 system, then they don't need to rate the partitions.
 
RLGA said:
Green board (or more appropriately, moisture-resistant gypsum board) is not required behind showers, and is not permitted when the showers have tile installed over the board--only glass-mat water-resistant gypsum board or cementitious tile backing panels are permitted. If you want some level of water-resistance behind the shower walls, you can get water-resistive Type X panels that will provide the fire-resistance and water-resistance characteristics in a single panel, thus eliminating the two layer application. However, the panel must continue to the floor to provide the required fire-resistive assembly.
Click to expand...
:agree

I agree

Refer to The Gypsum Association FIRE RESISTANCE DESIGN MANUAL, see figure 1, Section Through Typical One-Hour System. It is a tub, but a shower pan is the same...
 
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I wish. I'm providing an NFPA 13 system (mostly to avoid draftstopping the attic) but that doesn't get me out of rating the partitions. It gets me down to 1/2 hour per 709.3 exceptions 1&2 (2009 IBC) but they are still required to be rated. Now if someone would come up with a 1/2 hour assembly...

brudgers said:
If they install an NFPA 13 system, then they don't need to rate the partitions.
Click to expand...
 
brudgers said:
If they install an NFPA 13 system, then they don't need to rate the partitions.
Click to expand...
chris kennedy said:
Code reference please.
Click to expand...
R302.3 Two-family dwellings. Dwelling units in two-family dwellings shall be separated from each other by wall and/or floor assemblies having not less than a I-hour fire-resistance rating when tested in accordance with ASTM E 119 or UL 263. Fire-resistance-rated floor-ceiling and wall assemblies shall extend to and be tight against the exterior wall, and wall assemblies shall extend from the foundation to the underside of the roof sheathing.

Exceptions:

1. A fire-resistance rating of 1/2 hour shall be permitted in buildings equipped throughout with an automatic sprinkler system installed in accordance with NFPA 13.

One hour to 1/2 hour, not unrated....
 
Interesting that the 19th edition doesn't have that figure. I did find it in the 18th edition. That is exactly the detail I'm trying to avoid. Was wondering if anyone has maybe provided solid 2x wood blocking that matches the depth of the shower pan rather than that extra layer of Gyp. I guess I should quit trying to find a clever way out and hammer out the change order for the extra Gyp...

mark handler said:
:agree I agree

Refer to The Gypsum Association FIRE RESISTANCE DESIGN MANUAL, see figure 1, Section Through Typical One-Hour System. It is a tub, but a shower pan is the same...
Click to expand...
 
nealderidder said:
Interesting that the 19th edition doesn't have that figure. I did find it in the 18th edition. That is exactly the detail I'm trying to avoid. Was wondering if anyone has maybe provided solid 2x wood blocking that matches the depth of the shower pan rather than that extra layer of Gyp. I guess I should quit trying to find a clever way out and hammer out the change order for the extra Gyp...
Click to expand...
That detail shows the right way to do it
 
I'm not worried about what the board is (green, cement, water resistant X) none of that eliminates the need for the two layers since the second layer is only there to push the finish (swanstone panels, not tile, in this case) out over the lip of the shower pan (see image attached to my original post).

As you noted "the panel must continue to the floor" that can't happen with one layer if I'm putting in a shower pan that has a flange that the finish needs to overlap. I suppose I could put 1/2" blocking of some sort behind the shower panels but I suspect I'll get an uneven surface that sounds hollow and complicate grab bar attachment etc.

Thanks for everyone's input. Love this forum!

RLGA said:
Green board (or more appropriately, moisture-resistant gypsum board) is not required behind showers, and is not permitted when the showers have tile installed over the board--only glass-mat water-resistant gypsum board or cementitious tile backing panels are permitted. If you want some level of water-resistance behind the shower walls, you can get water-resistive Type X panels that will provide the fire-resistance and water-resistance characteristics in a single panel, thus eliminating the two layer application. However, the panel must continue to the floor to provide the required fire-resistive assembly.
Click to expand...
 
nealderidder said:
I'm not worried about what the board is (green, cement, water resistant X) none of that eliminates the need for the two layers since the second layer is only there to push the finish (swanstone panels, not tile, in this case) out over the lip of the shower pan (see image attached to my original post).As you noted "the panel must continue to the floor" that can't happen with one layer if I'm putting in a shower pan that has a flange that the finish needs to overlap. I suppose I could put 1/2" blocking of some sort behind the shower panels but I suspect I'll get an uneven surface that sounds hollow and complicate grab bar attachment etc.

Thanks for everyone's input. Love this forum!
Click to expand...
So, the shower pan edge with the lip will not be up against the first layer of gypsum board? Is the lip so thick that it requires the extra layer or shiming to allow the installation of the solid surfacing material?
 
nealderidder said:
I'm not worried about what the board is (green, cement, water resistant X) none of that eliminates the need for the two layers since the second layer is only there to push the finish (swanstone panels, not tile, in this case) out over the lip of the shower pan (see image attached to my original post).As you noted "the panel must continue to the floor" that can't happen with one layer if I'm putting in a shower pan that has a flange that the finish needs to overlap. I suppose I could put 1/2" blocking of some sort behind the shower panels but I suspect I'll get an uneven surface that sounds hollow and complicate grab bar attachment etc.

Thanks for everyone's input. Love this forum!
Click to expand...
I did not see an image attached to the original post. Did I miss something?
 
imhotep said:
I did not see an image attached to the original post. Did I miss something?
Click to expand...
attachment.php
 
Mark inserted the image below that illustrates the situation (how did you do that Mark? I inserted an image and just got a link.)

The detail on the right is the correct way to do it (at a rated wall), the detail on the left is at a non-rated wall

RLGA said:
So, the shower pan edge with the lip will not be up against the first layer of gypsum board? Is the lip so thick that it requires the extra layer or shiming to allow the installation of the solid surfacing material?
Click to expand...
 
nealderidder said:
Mark inserted the image below that illustrates the situation (how did you do that Mark?
Click to expand...
You type in


Add a link with www or http where I posted add a link
 
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