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How to build shower pan with my drain pipe

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Oct 30, 2013, 09:57 AM
How to build shower pan with my drain pipe
I am looking into tearing out my old basement bathroom shower and build a shower pan for tiling. From looking at many other websites and images I have found that my current shower drain pipe appears to be different than the ones I am seeing online (typically 1 straight pipe coming up). My drain (see image below) is like a bowl shape and then a pipe at the bottom which is where the water level is at. In the bowl area there is also another drain that is capped. I haven't taken the current shower pan off to see exactly what it looks like under there (I wanted to try and get an idea of what I am getting myself into) but it appears the top of the "bowl" pvc is where the basement floor is at.

My question is what do I need to do with the current drain so I can build a cement shower pan for tiling?


Shower drain

Oct 30, 2013, 04:08 PM
that is a floor drain that somebody built over. there could be a service drain coming into the side, or it could be somebody mislaid or broke the plug that would be in there if there wasn't a service drain.

I suspect somebody skilled in the trade like Frodo would say there are 6 colors of illegal here by current code, and you're bound by it since you started working with the shower.

assume there is a washer or laundry tub run to this floor drain bowl. that has to be replumbed with correct venting and a trap to the main drain run. the floor drain would be removed after breaking beaucoup concrete, a trap added, a line run up to become the shower drain. there would have to be venting added to the stack.

Oatey website shows how to build a mud pan using their membrane and cement. the alternative would be to buy something like a Kerdi pan kit or a precast ABS drain pan, instead of a mortar/liner/cement mud pan.

whether local or national code demands the basement have a floor drain to replace this one, and that would be fun because you've already decided to take the low spot away, I cannot say.

best move is to relocate your shower plans and plumb correctly, put a grate over this floor drain, and not get into the multiple fixes required. the previous shower was a quick hack if they used the floor drain.

This message has been edited. Last edited by: swschrad,

sig: if this is a new economy, how come they still want my old-fashioned money?
Oct 30, 2013, 04:55 PM
Thanks for the info swschrad. That is definitely not what I was wanting to hear Frown Now that you said it I should have known it was a floor drain because there is another one about 10 feet away in the maintenance room where the laundry machines are. Is that strange to have two floor drains so close?.

I haven't started any work in the bathroom yet but relocating the shower isn't really an option because the rest of the basement is finished and it is a very small bathroom (shower, toilet, sink all crammed in).

My original thought was to see if I could screw a pipe into the bottom drain (it's threaded), connect the shower drain to that and just fill in the bowl of the drain with cement. Because this would remove the possibility of accessing the capped hole what would the possible implications of doing that? What would be the better (more to code) way of doing it?

Oct 30, 2013, 09:07 PM
heres what i would do.
bust the floor you can dig down and uncover
what ever you have there...what your looking for is a 2" ptrap. or a 3" is a bonus...4" would be a trifecta lol
dig it up and expose it...then. firure out where your shower will be. how close is the closest wall?
you need to find the vent for that drain..
it should be within 5' of that drain if 2"drain or 10' if its 3" drain
Oct 31, 2013, 11:56 AM
thanks Frodo for your input. A couple questions before I go down the path of busting the floor. Since there is standing water at the top of the pipe wouldn't that indicate that there is some kind of ptrap already in? Would it be easier to have a plumber put a scope down the drain to look at it that way?

The cloest wall is about 16" from the drain.

If I have to dig 5-10' around the drain that will be an issue because the bathroom is small and the rooms surrounding are all finished.

Below is a diagram of how the bathroom is currently laid out. What also has me confused are the 2" pipes which come out of the ground (within the bathroom walls), go up to the 1st floor joists and connect into another pipe (I think it is the kitchen sink drain pipe) and then go back down into the basement floor next to the other floor drain in the laundry room.


Bathroom layout

Oct 31, 2013, 02:54 PM
OK, so you have two 2" DWV (drain/waste/vent) lines availiable to you. that they are interconnected means at least one should be going to a legit vent stack, which you can verify (sort of) by looking on the roof for vent stacks, then correlating to the windows of the rooms you know.

whether they are going deep enough to tap a sanitary Y in underground and get a P-trap in for the requisite fixtures is something that you can only find out by cracking some floor where you want to use the drain and going over to the line.

if not, heck, put the sand back in and mix some concrete when you are ready to patch the floor. nice to undercut the cut, so if there is any turgor pressure from rising water, etc. it will push the patch UP and make it stronger. probably best to use some bonding primer on the old concrete before pouring new.

local code probably requires permits and inspections fiddling with drain lines, just as a reminder. a toilet probably requires a minimum 3 inch drain for the less-liquid stuff it takes in. if new work is needed, best to have that plumbed for you out to stubs.

sig: if this is a new economy, how come they still want my old-fashioned money?
Oct 31, 2013, 06:45 PM
use a wet vac to suck the water out of the pipe
using your tape measure,,stick it in the pipe..does it go around a ptrap bend? or around a elbow?
you going to need to bust up the floor to get ahold of that trap...if you want your drain in another location. other than where it will need to offset BEHIND the trap. then instsall a new NEVER want to offset above the trap..causes blockage later in life
the vent pipe that is close to the trap is most likely the vent your looking for
you have pictures of the room? instead of a drawing?
Oct 31, 2013, 06:48 PM
looking at your drawing...the pvc pipes are vents for the shower drain and the toilet/wet vent sink
...dont take my word on it...all i see is a drawing
Oct 31, 2013, 07:00 PM
in plumbing, you haver a main sewer line under the floor
a "branch' comes off the main up to your k-sink
a vent comes off the toilet piping and goes up thru the roof
the shower has a vent also
thats 3 pipes..
if there is a washing maching there will be another vent
vents can tie togather, above the fixture
in the ceiling of the basement, the ksink vent can tie into that vent pipe, above the ksink or above the 1st floor
Oct 31, 2013, 07:28 PM
heres what you have....maybe

Oct 31, 2013, 07:32 PM
i dont know what i did,,but that picture is jacked up!!!
Nov 01, 2013, 01:13 PM
Ok so I looked at the drain again and I'm confident I have a drain similar to the one pictured below. I was able to get the cap off the side drain and then I ran a pipe snake down the bottom hole (through the water) and I was able to see (through the side drain) the wire coming back up and continue down the pipe it is attached to.

I do not intend to move the drain anywhere else which is why I asked if I could just screw a straight pipe to the bottom of this drain and connect the shower to that (I intend to pour a cement shower pan to tile).

I can't really make out the diagram you posted so I can't comment if that seems right for my plumbing or not.

It seems I can only attach one picture per post so I will post a couple picture of the bathroom in the following messages.


Floor Drain

Nov 01, 2013, 01:14 PM
Here is the current shower stall. The vent pipe is going through the wall on the right.

Shower stall

Nov 01, 2013, 01:15 PM
Here is the other half of the bathroom with the toilet and sink. The other vent pipe runs through the wall behind the sink.

Toilet and sink

Nov 01, 2013, 01:19 PM
Here is the vent pipe coming up through the wall on from the laundry room. The pipe from the bathroom sink connects in and then the pipe going parallel to the floor joists connects to another pipe which goes back down in the floor (shown in the next pic).

Vent pipes

Nov 01, 2013, 01:20 PM
Here is where the vent pipes connect to and go back down in the floor next to the other floor drain.

Other floor drain

Nov 01, 2013, 01:28 PM
ok....that ptrap...gotta come out.
build your wall for the shower....dry fit the shower in the hole, its going to live in...plumb it, level it
just like it was set..using a marker...draw a circle.on the floor..thru the drain hole
remove the shower unit..measure, from the back wall
and from the side wall the center of your mark/circle
bust the floor, and cut the trap off, offset the pipe with new trap to your center measurments. do not glue the peice coming thru the will glue it when you set the unit
any of that make sence?

shower drain

your going to need one of these,,,and some plumbers puddy
if ho depot dont have it, go to a plumbing supply house.

This message has been edited. Last edited by: Frodo,
Nov 01, 2013, 01:58 PM
I apologize for my ignorance here but could you please explain the reason why this trap has to be removed? The only difference I see between this drain and a standard trap is this floor drain has the side drain (which is capped) and it is a bowl at the top instead of a straight pipe. Could you provide a picture or link of the trap I should have in there? Maybe the drain that needs to go in is different than what I am thinking.

With the way other projects have been going with this house I fear this could get worse before it gets better (and with a lot less money in my pocket usually). I thought this would be easy and I could screw a straight pipe to the bottom of the current drain and then attach a shower drain to that (similar to the one pictured below).

What you mentioned makes sense but I am not using a shower unit to replace the one that is there so there is no option to mark a location on the floor and remove it. The plan is: there is a small storage closet to the left of the shower; I’m going to remove that wall to make the shower bigger. I then want to tile the whole shower. I plan to make the shower pan from cement (probably using the perfect pitch kit), so the drain can be anywhere and I will pitch the cement to that location.

Thank you for your help in this.

Shower Drain

Nov 01, 2013, 02:40 PM
tile floor, you need this drain has a flange on it to attach the shower pan water proofing membraine to
so it dont leak.
the ptrap you have is ilegal, its a roof drain with a overflow./condensate need a regular 2" pvc p trap


This message has been edited. Last edited by: Frodo,
Nov 01, 2013, 02:56 PM
look at the has a "bypass" drain hooked to the "bowl" of the fitting,
a ptrap uses a water seal, the trap keep out sewer gas...the trap you have, has a bypass built into it. it bypasses the water seal...and will make your house smell funky as a monkey it?
orderrifferious/who farted? whats thast funky smell?