Remove shower and install tub.

[bdailey]

I currently have a 42"x60" shower stall that needs a new tile floor. It is built on a concrete slab. Since we are going to have the remove the shower pan down to the concrete slab we want to put in a whirlpool tub instead. The shower stall has a center drain. We want to install a tub with a left side drain. How is the easiest way to accomplish moving the drain from center to left. Also what is the difference between the shower drain and a tub drain. Everything is pvc, I know that the shower drain is bigger than a tub drain so I will have to have a reducer. I guess the big question is the drain location since it is on a concrete slab. I have been thinking of two appoaches. First would be to cut open the concrete floor and move the drain. The second would be to build a platform for the but to sit on and run a connecting pipe from the left side tub drain the the existing shower drain. I know I need a trap for the tub drain. I am not sure if the shower drain already has a trap (how can I tell?). Also venting, how can I tell if the current shower drain is vented? Sorry for the long post. Thank for any help anyone can give.

 

[havasu]

I would bust out some concrete and reroute the plumbing, rather than placing the new unit on a pedestal. This way, you can confirm whether the trap is installed, and add a reducer if necessary. Yeah, it may me a little more work, but would be a cleaner installation.

 

[bdailey]

How is the best way to cut the concrete? Also what about a tub with a center drain? Do they exist? Thanks for the help.

 

[havasu]

I've used a concrete saw blade to score the concrete, then followed thru with a sledge. I did end up getting a roto hammer for some of the hard to sledge areas, but it wasn't too hard to remove. Yes, some high end tubs have a center drain, but they are costly and very limited, not to mention difficult to install on a slab.

 

[Chris]

Inexpensive ways of cutting concrete are with an angle grinder that has a concrete blade or you can get concrete blades for a skil saw. Just cut as deep as they will go and then bust out the rest. If you have a shop-Vac bring it in with you when you cut and have it suck most of the dust from the saw or you will have a bit of cleanup to do.

 

[bdailey]

I really don't want to have to cut a path in the concrete but if that is the only option then I will. I was thinking since we are getting a drop in tub and I already have to build a frame for the tub it would be easy enough to build a platform for it to sit on. I was thinking of building a platform from 2x4's and running under it from the tub to the existing shower drain. The distance would only be about 3 ft so I can still slope it 1/4" per foot for proper drainage. I guess my question is will this cause any plumbing problems. I know the trap should be directly under the tub drain but would it hurt it to be 3 ft away by using the existing shower trap? Any tips for suggestions would be greatly appreciated. Thanks again for the help.

 

[havasu]

It would depend on the manufacturer of the tub. If it is fiberglass and it instructs you to have full support under the base, then building it above the base will cause it to collapse when you fill it with water. Your best bet is to contact the tub manufacturer themselves, and find out what they have to say.

 

[Chris]

Havasu what are your opinions on building the frame up then doing the plumbing and then pouring a concrete pad for the tub to sit on so it will be like sitting on the slab? Although I do agree that cutting out the concrete is the best way this would just be what I would think of doing if I couldn't cut the concrete.

 

[phishfood]

I have done something similar several times. The key is getting good support underneath the tub, which pouring a second "floor" would do. You need to make sure that the concrete contacts the tub pretty much under the entire tub bottom. Even if the tub doesn't break, it will tend to squeak when stepped in if the bottom isn't fully supported.

One problem with this approach is that the tub has to be raised a considerable distance to use a conventional tub drain arrangement. There needs to be room for a 90 ell to turn from the vertical riser to a horizontal plane, then another 90 ell to turn back vertical, then a sanitary tee to attach the waste and overflow to. To get around some of the height problems, you can aim the horizontal run of pipe somewhat to the side of the drain outlet and use a wye fitting to attach the drain waste pipe to. Then use a 90 ell to turn back to the vertical, and 2 45 ells to offset back to the overflow.

Although, if it were me, I would cut and break out the floor to reroute the drain.

 

[havasu]

^ Yeah, what he said!

 

[bdailey]

I guess I will be cutting the concrete it is only about three feet over. What kind og angle grinder do you rommend? How powerfull and what size? Thanks again for all the great info.

 

[havasu]

If you have a Skil Saw, you can purchase the concrete blades fairly cheap. They wear down quick, so I would get a few of them. The angle grinder works, but since their blade is a small diameter, divide that in half and that will be your deepest cut. a 7 1/4" Skil Saw blade will get you at least 3", and your slab should only be an inch or so deeper than that.

When I did the opposite (took bath out to install a shower) I had a fairly large opening where the drain went thru the concrete. It had a bed of gravel, making it a quick and easy job to move my drain forward 15". As recommended earlier, a shop vac is a must to keep the dust down!

 

[Chris]

I don't recommend those black composite blades at all. spend the extra couple of bucks and get a diamond blade, you will be much happier and will get to keep the blade a little longer.

 

[havasu]

Very true, and they don't throw their medium all over. The downfall is the costs for a good diamond blade.

 

[Chris]

Heck go to Harbor Freight and get a cheap one, still ten times better then those black ones.