I am at home bored and finally decided to finish the bathroom in the basement. The rough-in was put in when we first had the house built. I figured this will be a fun project and plan to work on it on the weekends. The rough-in was originally set up for a sink, toilet, and a bathtub with a shower. I would like it to be a stand up shower only. After doing some digging on how to convert a bathtub to a shower I had planned to apply those principles to my design. I move the wall out a bit finished most of the framing for the bathroom then today I found a post that says a shower drain should be 2". I measured my drain for the bathtub and its only 1-1/2" so my first question is when people convert from bathtub to a shower does the drain become an issue? Based on that I guess I have to rethink my plans.

Thanks in advance,

Henry

 

You just have to cut the floor out in order to change it. Not a big deal, it's done all the time. Probably have to cut out 8 feet at the most to get over to the stack or main line.

 

Don't ask me why a dedicated shower needs 2" when a tub/shower combo is OK with 1 1/2" but that's the code. It is NOT permitted to use 2" fittings on the shower and connect to your 1 1/2" drain line. It must be 2" all the way until it meets a larger diameter pipe.

 

Sleeper and Pilot Dane thanks for the info. I may have to rethink the shower idea. Bad part is moved the wall out already. I had been watching a bunch of videos and none of them mentioned the 2" drain...lol. Glad I did some more research here. I am going to figure out a way to let my wife know I need a jackhammer to finish the the project...lol. I guess I will continue to my first question on my plumbing. Above the entry of the door there are two pipes. One is a 3/4" the other is 1/2" my thinking is the 3/4" will be the cold water line since it needs to supply the sink, toilet, and the shower. Is that correct?
How soon should I reduce that pipe down to 1/2" for the fixtures and toilet? The layout of the bathroom is off a little. The sink and toilet are on the same wall while the bathtub/shower plumbing will be on the opposing wall. The bathroom calls for a 30" sink and they did not run the sink drain far enough over so i will have to redo that part as well. I think I want the hot and cold water lines along with the drain to be in the center or close to center as possible for the sink. Normally plumbing is coming from the floor and the cold and hot water lines just go through each stud. What would be the preferred approach for the bathroom layout or some suggestions?

For reference here are two pictures of what is currently there...the picture on the left is the back wall where toilet and sink will be located. The right is where the rough-in for the where the tub was supposed to go.

Thanks in advance,

Henry

 

The only way to know what pipe is hot or cold is to trace them back or run some water and fee which gets hot. Yes, I agree the larger is probably the cold but you never know until you trace or test it.

If the 3/4" is the cold water I would treat it as a trunk line. There are "T" fittings that go on 3/4" pipe and have 1/2" T off to the side for individual fixtures. For the last fixture in the run you can simply reduce to 1/2".

How you run the water lines is up to you. They can drop down from the ceiling or you can run them through the walls. It usually comes down to which is easier, which allows shorter pipe runs and I also try to minimize 90° fittings.

 

Seems to me that there was a thread not so long ago with a similar issue and the questions was asked, why are shower drains 2"? I believe someone brought up that the code had recently changed and 1 1/2" shower drains were now allowed.

Here is one:

https://www.acehardware.com/departme...E&gclsrc=aw.ds

 

I am starting to frame out the half/knee wall and the small bench area. I am not finished and need some more boards for sturdiness. For the top of the knee wall and the curb what is the general guidance for slope? I have been researching and it seems there should be no flat surfaces in the shower area. So how is the amount of slope calculated. Do I just need to make sure its on the 1/4" per foot rule? I guess I am wondering how the glass will sit correctly on the top of the knee/half wall. Any insight would be greatly appreciated.

I also am adding in some new framing for the 16" OC suggestion for the 1/2 backer board or other 1/2" membranes. I wish I would have know about that before I did the 24" OC to match what was already there.

 

Knee walls are very difficult to give enough structural strength. Simply toe nailing studs is not enough especially if you will be tiling. I use the biggest metal brackets I can fit where the knee wall meets the sole plate and a good floor to ceiling stud.

 

Pilot Dane,
The picture above was just some dry fitting to see if I had the height my wife wanted. I still have a long way to go. The drain needs to be moved, more studs to conform to the 16 o.c suggestion, deciding on the shower pan DIY or purchasing a prefab so nothing has been nailed yet. One of my concerns when she asked for the half wall was stability so that was one of the first things I researched. As soon as I searched for knee/pony/half wall stability was one of the top things that popped up...lol. Seems like stability issues and the wall go hand in hand...lol. At first I wanted to run from the project but figured why not make it look like what she wants. I may use a brace or threaded rod solution that I saw. I just have not been able to find the suggested amount of slope for the top of the wall or the curb and if there is a standard people use. Thanks for the reminder though, your picture lets me know I am on the right track...these are a few I have in saved examples folder including yours.

Thanks,

Henry

 

I would put a slight 1/8" to a max of 1/4" per foot slope on top of the wall and dam. There is no code requirement but if any water leaks around your glass or door you want it to flow back into the shower.

 

Great! 1/8" sounds much better for the wall and probably not that noticeable with the naked eye. I was playing around with 1/4" and kept saying to myself this is gonna slant too much when glass was applied. When I apply the top I will just shim the outside. I will probably do something similar on the curb but don't mind that being 1/4" since water is definitely more likely to get on curb more often.

 

My buddy is supposed to finally be bring by the jack hammer or something to break the concrete with on tomorrow. I have made some progress where I reframed most of the room to 16" o.c. based on more research about backer board options. I connected the plumbing to the rest of the house and after one day there were no leaks. So I have insulated the ceiling and finished the plumbing to the best of my ability based on how the room was laid out. I started on the walls and I have a. question about the shower area. The back wall is an exterior wall so I think I need insulation on that no matter what the side wall and the front of the shower are interior walls. Do I also need to insulate them as well?
Attachment 115208

 

I got a few days of progress done but still need the question above answered? Do I need to insulate the back of the shower (outside wall...below grade) and the wall seperating the shower from the workout area (where the pictures are)?

 

What did you decide on the shower drain? Changing it all to 2" or staying with 1 1/2"?

 

Exterior walls are ALWAYS insulated. Interior walls are optional, and if you did it the benefit would only be for sound deadening, which would be minimal on a 2x4 wall.

 

CasualJoe,
Dang I forgot to update on that. The test cap that was on it threw me off. It looked small since I am use to plumbing my fish tank and any end caps are beefy. When I actually measured they had plumbed everything with 2" so I was good to go. It was pretty easy once I removed the concrete to move it to be a center drain.

 

XSleeper,
Thanks for the info.

 

Here is some of the progress. So far I have completed the drywall, reinforced the knee wall, moved the drain, installed insulation up until the part in question, cut some of the backer board for a dry fit, and built a custom vanity. I need to get to the tile shop to pick up some Laticrete thinset this week hopefully and install the pan and maybe the rest of the backer board.