Bathtub Issues

This is my first time posting but ive been looking through the forums and got a lot of great information!

I just ripped out the one piece fiberglass tub/shower in my bathroom and am eager to put in my new kohler cast iron tub then have tiled walls but came across several problems.

1) This is on the second floor and the floor is 3/4" plywood and underneath is what i believe to be crawlspace. How would i support the bathtub? Originally i thought i would simply nail some 2X4's to the studs of the wall to help support the tub when it is set in. However, after bringing the tub home i found that the bathtub flanges are not flush underneath. The drain side doesnt have a lip and was made so underneath there is a protrusion that is slightly parabolic which would make measuring where to mount the 2x4 to the stud difficult. The back has almost the same thing but has a 1/4" lip before that curvature. The side towards the wall has a lip so i can support that side very easily. How should i go about making support for this tub?

2) As stated, the floor is basically 3/4" plywood and would the tub be fine just resting on top of that with its legs? Do i have to keep it from moving somehow? it doesnt seem like it would move because we have a tough time trying to move it

3) The tub has a very small flange and i was under the impression that the backerboard is supposed to go over and on top of the tub. The flanges are very small and on the side the tub touches the wall, if i attempt to put backerboard over it and tile it then the tile will be pretty damn close to the well (where water sits) of the tub. I think it would look really awkward.

it is this tub
http://www.us.kohler.com/onlinecatalog/detail.jsp?item=408302&section=2&category=10

You can kinda see how small that flange(?) is.

Sorry for the long post. Im just trying to describe it as detailed as possible. This is my first time doing a project like this but i am very eager and motivated to finish it. I appreciate your help and it is GREATLY appreciated!

tub

Most tubs do not have room at the back, (that is the only side that needs it), for a 2x4, so use a 1x4. If the tub does not have instructions as to the height of it, measure the tub itself. The backer board comes down to the tub and the tile fits over the rise on the tub, and down to the tub's rim. The tub has little feet under it that set on the floor. The only time you might have to add support is if the front apron was parallel to the joists and about midway between them, and even then the feet should give enough additional support that it would not distort the subfloor.

To measure where to put the 1X4's would be hard because of the parabolic shape, only the corner of the wood would be touching the tub unless i shape the wood to the exact shape of the protrusion. Should i just not support the front and back?

Im just trying to verify, but do you mean the bathtub will rest against the backerboard and when tiling the bottom tiles will rest over the tubs mini lip?

And do i have to mount the bathtub so it wouldnt move? The people at home depot say i put nails over that small lip and bend them down or something, but this doesnt seem right if im going to tile over it.

buyos1717 said:

To measure where to put the 1X4's would be hard because of the parabolic shape, only the corner of the wood would be touching the tub unless i shape the wood to the exact shape of the protrusion. Should i just not support the front and back?

Im just trying to verify, but do you mean the bathtub will rest against the backerboard and when tiling the bottom tiles will rest over the tubs mini lip?

And do i have to mount the bathtub so it wouldnt move? The people at home depot say i put nails over that small lip and bend them down or something, but this doesnt seem right if im going to tile over it.

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I just read the installation instructions and it looks like that model tub is designed to rest on its four "legs"...no need for a ledger board.

Instead of nails, I like to use stainless steel screws and fender washers to hold the lip of the tub...of course, make sure you hit a stud.

Good luck.

If the only place there is a lip on the tub to secure it to the studs is on the long side against the wall i would search ,for some tub clips that are made to fit over the lip/flange edge,and provide a hole in the clip to fasten to a stud. I would think your tub would have came with a few clips. I would not use a nail and bend it over the lip as HD reccomended.(that could prove to be a slight problem especially if tiling..) I would not be suprised even if Kohler said no support is needed at the front and back...(provided the tub sits squarely on its four feet)being cast ironI would think is support enough at these points.. Cast iron is hard enough to bend if you get it red hot..
Using 1/2" backer board then figure your thin set and the thickness of the tile your using you will be damn near flush with the bath well or exceed it.. If the room you have to the curviture is only a 1/4" you say? The minimum bottom of lip/flange to curviture i have worked with on a tiled in tub is 1 1/4".
Happy Tubing

Oh well... now you understand why a $60-$90 per hour plumber would have it done in 2-3 hours and a DIY'er is going to take two weeks. Just a lot of "figuring out" that a typical experienced plumber is going to have done ahead of time.

Randyj said:

Oh well... now you understand why a $60-$90 per hour plumber would have it done in 2-3 hours and a DIY'er is going to take two weeks. Just a lot of "figuring out" that a typical experienced plumber is going to have done ahead of time.

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Correct me if im wrong but i dont think that a bunch of experienced plumbers come on this site to ASK questions. I realized that i was going to have a tougher time on this project then a paid plumber but i dont expect this to be the last time i do a project like this. Maybe im taking it the wrong way but i found your response to be somewhat like a jackass response.


As for all the other responses, i thank you for your help because it has been a great amount of help. I dont expect this to be my last project so hopefully i will be able to contribute what i learned to others on this site. Thank you!

I won't inflame things, but will throw in my two cents.
"so-called" professionals, whether they are plumbers, carpenters, landscapers, painters, etc. etc. are very hard to find!!!!! Quadruple Exclamation.
Personally, I have given up trying to hire anyone to perform construction, and repairs on my house.
Over the years, while trying to keep things fixed up at my mothers house, my fathers house, and my two houses, I have been burned more times then I can count. Overcharged, poor work, showing up when they feel like it..all the usual complaints.
If any professionals here at this site would like to promote the benefits of hiring an experienced contractor, by all means keep trying. I have stopped taking chances and won't call you, unless it is a dire emergency, (House burned down, or plane crashed thru roof, etc.).

This is the attitude of cash-strapped homeowners, that value every penny they spend.

Have you visited the technical specs page for your tub? It looks like you downloaded the picture from the kohler website..just find your model again and find the rough-in and installation drawings that should be posted there.

buoys... probably was... could've been one of them moods.... but for some reason some folks think this stuff is going to be easy... it ain't, and usually does take alot of time to figure out...and lots of mistakes are made before one becomes proficient at it. I've actually been very honest and serious when telling someone to get a second job so they could hire a plumber because I could have done a job in a day that was going to take them a month and they would have a screwed up job when they finished...even with top notch advice. Personally I admire anyone who is willing to get off his duff and do something himself rather than relying on others.... then I go before a judge who will not give justice unless I hire a lawyer at outrageous price to tell the court what I could have told them myself.... it actually happened to me in an uncontested divorce.

I admire that stuff too, keep in mind though, I'm sure you wouldn't want that Judge showing up on one of your plumbing jobs, helping out for free, playing with your tools and stuff, saying Ya, I've used a wrench before. Lastly, the end of your post sounds confusing, uncontested on the one hand, but you somehow were in need of justice?