One-piece Tub/Shower

Old 06-22-04, 07:02 AM
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One-piece Tub/Shower

I'm about to complete the install on a one-piece tub/shower and I have a few questions. First, I know it is recommended that I set the tub into a bed of mortar but since this is a one-piece I have to slide it into place and can’t really get the tub set into the mortar, is there a trick to this? Is the mortar really necessary if there is no bounce in the tub floor? Also, the one piece is only about 72” tall so I have to do something in the 24” between the shower walls and the ceiling. My preference is to just use green board and paint but I’m concerned about water damage. Should I tile or will the green board be ok?
Old 06-22-04, 08:19 AM
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Lack of support causes squeaks, in some cases leaks at drain pipe fittings and worst of all cracks in the finish material. Most manufacturers recommend or suggest installing a mortar base support under the tub bottom before setting the tub in place. You can use either a bag of Quikcrete or a 5 gallon pail of pre-mix joint compound. ( usually I use the pre-mix 5 gallon...lazy and it's less mess)

When this sets up, usually with 24-48 hours, your tub bottom will be rock solid supported. No squeaks or flexing which I assume it is flexing as well. This does 2 things, prevents any possibility of potential cracking within the fiberglass/acrylic and eliminates any movement at the tub drain assembly or potential leaks that could happen.

I don't understand about this "slide it into place" issue. This will be anchored directly to the studs. You should tilt it out once you get it back far enough and then rest it in place atop the mix. Then level it and anchor it.

One concern I have is the width of this one pc and current door openings. Height may be fine but the bathroom do may not. Check your measurements.

M/R rock is fine above the shower/tub unit. The issue is in direct contact with water and this area above is not, so drywall is ok.

Hope this helps!
Old 06-22-04, 09:02 AM
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Well the one-piece is already “dry-fit” in place so getting it into the space isn’t an issue. I have walked around in the tub and there is no flexing so I’m wondering if the mortar is necessary. I have to "slide it into place" because the control valve and tub supply pipe already extend from the wall. I have no access from the back side of this wall so in order to match up the holes in the one piece unit with the protruding pipes, I have to slide the one piece in from the end so that the holes line-up. This is where I am running into the problems with the mortar, if I slide it into place then I won’t get the same support as if I were able to set it in from above. Basically, I think that the mortar would get pushed around enough that it would be ineffective as a support. Are there any tricks for this? Is this not how a one piece is typically installed?
I’m glad to hear that the minor splashing from the shower on the green board will be ok ‘cus I really didn’t want to have to tile.

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