Installing firberglass/plastic tub

[GaryD]

I am intstalling a firberglass tub on a cement slab. Its not a one piece but has 3 other pieces as side walls.

The slab is slightly uneven (tub has a slight rock to it when I lay it in position without any walls around it) and I would like to level it while scuring the tub. I would like to simply spread some type of support bed and lower the tub into it and let it dry.

My questions are:
1. would this be an adequate way to level out the surface for the tub
2. what do I use as a support bed
3. what do you do if you ever have to remove the tub?

Any other suggestions?

Thanks, Gary

 

[Jadnashua]

This is done all of the time. Normally, you don't really care about when it must come out again...that's for the next person. There are several substances you can use on the floor - first, check the instructions to see if they have a preference. If not, then come back and somebody'll give you some suggestions. The bed doesn't need to be thick, but it should cover the bottom. Make sure the ledger boards around the rim are level and when you smush it into the bed, stop once it reaches that level position then leave it until the stuff cures. Depending on what you use, that could be 1/2 hour or a day.

 

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[Cass]

What brand of tub and walls is it?

 

[GaryD]

The tub is a Sterling by Kohler series 7122

The installation guide syas: Installation with optional mortar or cement bed.
Spread 2" layer of cememnt or mortar on the subfloor except where the bath feet will set.
Position a piece of plastic drop cloth material on top of the cement or mortar. Move the bath into position and verify that the bath is resting on all supports.

The tub installation does not call for any horizontal support just vertical supports to attach the clips to. I know this part has been discussed on the forum and I should build a horizontal rest under the lip of the tub on the 3 sides.

If I make a bed of cement or mortar do all the bath supports have to touch the cement subfloor. I am trying to level the area a bit and expect one side to be an 1/8 or so off the subfloor but embedded in the cement bed.

Should I use cement or mortar?
Thanks, Gary

 

[Jadnashua]

If all areas are supported, either by the feet or the mortar, you should be okay. What they are trying to prevent is the thing twisting, but that assumes that the floor is flat in the first place. What you could do is set it in place temporarily, and shim it level. Either use some glue or caulk or something to attach that shim to what ever feet need it so it sits level. Then, when you set it back down in the mortar, you can rely on the feet to tell you it is level.

The mortar under the tub is to give the bottom support - it makes the tub feel more like a cast iron one and keeps the thing from flexing and getting stress cracks thus lasting longer while looking good.

 

[GaryD]

Do I need to put plastic over the mortar before I palce the tub in position?
What is the plastic for?

The bottom of tub doesn't really have individual feet but has many supporting ribs that touch the ground. Should I just pick some and shim/level them before installing the tub in mortar?

Do I use mortar or cement or it doesn't matter?

Thanks, Gary

 

[Jadnashua]

The goal is 100% support to prevent flex. In this case, I'd just mark appropriate level lines on the walls and mash the whole thing down into the mortar or cement. You can use plaster, too which will harden quicker. There are some special products designed to do this, but something like deck mud (4:1 mix of sand to cement) is probably the least expensive. That will take a day or so to cure enough to then continue with the installation. This stuff ends up acting sort of like wet beach sand in consistancy. The plastic helps when you want to remove it later...it doesn't allow the bedding material to stick to the tub. I guess, it could also sort of lubricate the thing to settle easier into the bedding material, but I can't tell you that from experience.