Bathtub Install...

[Greg Cuetara]

Short story is that I have a bathtub on my second floor. There was a leak down into the first floor ceiling so tore out the tub and enclosure to find the culprit....i think it was the drain but while it was all out LOML decided that she wanted a new tub etc.

Found one at Lowes which has a nice curved front on it. American Standard Saver.

Under the tub there is a large piece of chip board which basically supports the tub and then under that are two stringers which extend the length of the tub. The stringers are about 1" wide and 2 3/8" deep. The instructions say, "We recommend the use of mortar as bedding material. Apply enough bedding to support the complete bottom of the bath."

Should I be filling the entire 2 3/8" gap with a mortar mix? It seems a bit odd to me to have the stringers and then also have to put down a mortar mix. I was thinking that I might build up the distance between the two stringers with some advantec and either get up to the underside of the chip board or close enough so that there wouldn't be much mortar.

Any thoughts out there on the creek? Or should I not worry about it and just install it as is and forgo the mortar all-together. Again my first plan was to just use plywood to build up the floor to fully support the tub. I was going to glue and screw it down. But I read the instructions and it says to use mortar...

I will probably call american standard tomorrow to ask them but wanted some other opinions.

Btw I am not keen on mixing up a mortar mix which is why I was trying to find an alternative.

Thank you,
Greg
tub2.jpg

[Wayne Lomman]

Greg, you need to bite the bullet and use the mortar mix. You need it to support the weight of water and person(s) otherwise the bath will flex and break the waterproof joints over time and maybe the bath itself. Mortar is cheap and it conforms to the bath shape easily. Just get a few bags of the premix from a hardware. You would regret short cutting this. Cheers

[Steve Eure]

How about concrete board. Lowes sells it and it is made to put around tubs, showers, and floors in the bathroom..

[Mel Fulks]

Was the morter always reccomended or that new ? Seems like when I've seen them in places being renovated they did not have that, but did have more support built in.

[Jerry Bruette]

When We remodeled our bathroom we put in a shower which replaced a fiberglass tub/shower. I followed the directions and put it in a bed of mortar, that shower is solid.

The tub/shower unit in our other bath is not in a bed of mortar and it creaks when it's used.

It took less than two bags of mortar to bed the shower, so it's not a big deal to do it right.

I've heard of tub/shower units cracking and leaking if not supported properly.

A fellow I work with said he used Great Stuff to bed a tub he installed. Said he filled the tub with water then drilled holes in the floor and filled from below with Great Stuff. I don't think I'd trust it over the long run though.

Good Luck

[Lee Schierer]

How about concrete board. Lowes sells it and it is made to put around tubs, showers, and floors in the bathroom..

No use mortar. You want a noncompressable material under the tub, great stuff and foam is not adequate support. Mix it thin, but not so thin that it flows under its own weight. When you set the tub on the wet mortar the stringers will sink into it creating a continuous and solid base for the tub. You don't have a lot of time to set the tub so be sure that it fits in the space first and that you have adequate help to get it in place quickly. Make sure it sets all the way down where it should go. You should not pull it back out for any reason or you will have to start over.

[Greg Cuetara]

Thanks for the advice.

[roger wiegand]

OT, but I wonder when the switch to mortar happened? 20 years ago one used plaster of paris.

[Chris Padilla]

I am in the process of installing my own new American Standard tub. The directions that came with the tub call out to use mortar to support the entire bottom of the tub. My tub is a 3-wall alcove tub with a built in apron. My tub won't even sit level on the floor by itself as the bottom of the tub is a couple inches up from the apron so I HAVE TO use the mortar mix to properly level it.

Mixing mortar may not be fun but a 5-gallon bucket and < $20 paddle mixer coupled with a halfway decent drill ought to do you fine.

For my tub, I have to first screw 1x4 stringers to the wall to level the tub and then I pour the mortar mixture to embed the tub into. It is important that all the weight of the tub rest on the mortar and not on the stringers. The stringers are there only to aid in leveling the tub.

Mapei 4 to 1 is a great bedding material and usually available at Lowe's. This type of mix is often used as the base for mud bed showers.

Skip the italicized advice above. Use a Mason's Mix or Mortar Mix to embed the tub. It is also a good idea to lay down some tar paper or thickish plastic (4 mil or greater) on the plywood and then dump the mix on top of that. One might also consider adding a very thin sheet of plastic (like saran wrap thin--1.5 mil) to the top of the mix to keep the tub from sticking as this will facilitate future removal.

[Greg Cuetara]

Chris that sounds like a very similar tub to mine....i'll probably just suck it up and do it i was trying to see if there were other options that i didn't know about. I did find a $6 paddle mixer at harbor freight which might do the trick to mix one or two bags. Always something fun to do with home ownership!

[Rich Engelhardt]

OT, but I wonder when the switch to mortar happened? 20 years ago one used plaster of paris.

Mortar is cheaper...

Btw I am not keen on mixing up a mortar mix which is why I was trying to find an alternative.

You could always go to an acrylic, like a Kohler. Kohler doesn't need to be bedded in anything. You just shim the feet underneath.
Course that brings up it's own list of nasty things you have to do to get access to those feet. Both times I installed a Kohler acrylic, I had to enlarge the drain area from underneath and knock a big hole in a bedroom wall to get at the feet on that end. Well, not just to get at the feet, I had to knock a hole in the wall to slide the tub through.

[Jerome Stanek]

I like cast iron tubs

[Randy Red Bemont]

OT, but I wonder when the switch to mortar happened? 20 years ago one used plaster of paris.

Back in 1999 my builder used sheetrock compound. It worked great. Put down a layer of tar paper before using any mortar or compound. It will hold moisture (even from the air) and rot your subfloor!

Red

[Chris Padilla]

I like cast iron tubs

Try lugging one of those up a flight of stairs and then try maneuvering it. A 5' tub into a 5' space can be tricky! I wanted cast iron initially but then came to my senses.

[Mel Fulks]

Well....all real film buffs know that cast iron tubs can really mess up a good chain saw