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mslide 07-09-2008 11:47 AM

redoing basement shower - basic questions (relocating drain/options I have)
Greetings all,

My house is approx. 50 years old. In the basement is a very small bathroom, with a very small shower, that I want to redo. I have the entire bathroom gutted. My question is about the shower and my options. It has a cement shower pan, right on the cement floor of the basement. It is 27" x 27". I checked the local building code and they said minimum size needs to be 30" x 30". No problem, as the surrounding rooms are not finished and I have no problem relocating a wall or two to accommodate a larger shower. The shower drain is not in the middle of the pan. It's about 12" away from the wall with the shower head (I can't really move that wall).

Given that, what are my options? All of the prefab shower kits and pans I see require the drain to be in the middle. If I have to move the drain, I'll do that, even I really don't know how (but I'm always open for tackling new projects). What about building a mortar bed?

Lastly, I'm a newbie at this kind of bathroom remodeling. I am up to any challenges, but I'd like to take the simpler of any options. I know I'm being vague, but we don't really care what the shower looks like, as long as it's nice. Pre-fab, tile, whatever.

Here are some specific questions:

Can I bust out the existing cement shower pan without damaging the basement cement floor or should I assume that if I do this, I'll have to fix the cement floor underneath (even if I don't move the drain)? Any tips for doing this?

Do shower drains include a trap, like sinks and toilets?

If I go with a mortar bed, I assume the drain can be anywhere I want it (and thus not have to move it) as long as the bed is sloped correctly...right? What's harder, moving a drain to accommodate a shower kit or building a mortar bed (I have friends who can help me with tiling).


Marlin 07-09-2008 04:19 PM

You probably have a lead pan. It's a piece of lead that covers the bottom of the shower and six inches or so up the walls. An inch and a half or so of cement is poured into the pan. The floor and walls are then tiled. You won't see the lead until you start breaking up the tile and cement. It's possible that you have some strange cement shower pan though with no lead underneath. Their is no way to tell without actually being there to look at it but the chances are high it's a lead pan.
You should be able to break it out without damaging your slab. No one can make and guarantees however.
If you go with another lead pan or the plastic that is now often used in place of lead you can keep the drain where it is so long as you properly pitch the mud. Keep in mind having the drain off center like that is going to look silly.
If you want to move the drain obviously you are going to have to open up your slab to access the pipes below. Shower drains do have a trap. In a basement they are buried under the cement.
Another thing to keep in mind is that you probably have case iron underground. How is the current drain attached to the case iron? Is it leaded in? Is it threaded in? Chances are you won't be able to unthread it if that's the case. If it's leaded in you may be able to dig the lead and oakum out and use a rubber gasket to install your new drain.

clasact 07-09-2008 11:07 PM

I had a similar problem and found a lead pan in mine I busted it out with out any damage to the floor and poured a new shower.The drain is still a little off but with the way it is tile it really don't look bad,If you do decide ti make you own shower their are several threads on here the deal with that topic and be sure to water proof.If you do put another pre fab pan in I am sure you can find an off set I just don't know if they make one for just what you need.Making your own is a bit of work but I really think thats the way to go I am on my second one now and its even more of a challenge then the first.Like Marlin said the trap is in the slab or concrete and you probably wont get it apart so if your willing to make your own why get into busting up your slab

mstplumber 07-10-2008 08:22 AM

Since your house is already 50 years old and you are going to the trouble to redo your basement, you might want to consider breaking out some concrete and moving the drain to where you want it. This will allow you to replace the trap. Since you do most likely have a cast iron trap that is 50 years old, it could be in really bad shape. It would be a shame to do all the work and have to tear it out again because the trap fails or stops up continually. P-traps hold water and, at least in cast iron systems, are frequently where problems develop due to corrosion and build up.

The good news is that it's not that big a deal to replace the trap with PVC and then move the drain a couple of feet to wherever you need it. This will also eliminate the problems you are sure to have dealing with the old drain assembly itself.

Once you've torn out the old shower, rent an electric jackhammer and break up the floor. You can cut the old cast iron with a special sawzall blade and use special coupler to hook the new PVC to the old Cast Iron. Once that's done you can decide what kind of floor you'll use. Whatever you decide you won't have to worry whether the trap is going to fail.

mslide 09-21-2008 12:42 PM

1 Attachment(s)
So I finally got around to doing some work on this project and I need a little advice from the experts.

Attachment 5125

edit: I wound up cutting the cast iron pipe, downstream of the hub with a soil pipe cutter. I had to dig up more concrete to do this. See next post.

PS. If anybody's interested. I'm not sure how to explain this, but there was no shower base. It was the concrete floor. It looks like when the basement slab was pored, they sloped it a little to form a shower base. Then they built little cement walls on all sides, that came out very easily with a sledgehammer. Digging up the concrete really wasn't as bad as I thought. On the advice of a carpenter friend of mine, I use a circular saw with a diamond tip blade to cut out a square. I then used a combination of sledgehammers, crowbars and shovels to do the digging.

mslide 10-28-2008 10:42 AM

Just thought I'd post an update on what I did plus I have a question at the end.

I wound up cutting the cast iron pipe/trap downstream of the hub with a soil pipe cutter. I had to dig up more concrete than what is shown in the above picture. I attached a new 2" PVC trap, with a no-hub coupling (the type with a stainless steel ring around it) and put it right where I needed it. Filled in the hole I made and poured the concrete leaving about a 6" diameter, 2" deep well around the drain pipe so the actual drain assembly would fit (the opening for the shower base sits right on the floor, so I need room around the drain to fit the drain assembly). I then rebuilt the remaining wall for the shower.

I've read that I should install a mortar bed underneath the fiberglass shower base so that it doesn't move. I've also read that you can use drywall joint compound instead, since it's easier to work with. Is it really okay to use joint compound for this? I definitely need something underneath the base because, while I leveled the concrete as best a concrete newbie like myself could, the base still wobbles a little. I've never worked with mortar before so if I can get away with a 5 gallon bucket of joint compound I will use it. What I was thinking was that when I am finally ready to permanently install the base, I'll pour in the joint compound, smooth it around and set the base in, pushing down on all sides and making sure it really is level, then nail the base to the studs and not disturb it for a few days before installing the drain's rubber compression/gasket fitting thing. Any comments?

Thanks everyone!


Originally Posted by mstplumber (Post 137797)
Since you do most likely have a cast iron trap that is 50 years old, it could be in really bad shape. It would be a shame to do all the work and have to tear it out again because the trap fails or stops up continually. P-traps hold water and, at least in cast iron systems, are frequently where problems develop due to corrosion and build up.

You were certainly right. The old cast iron trap was in bad shape. I'm sure glad I replaced it. I also made sure my new drain works properly by using a garden hose and running water down it.

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