How to install a shower drain in concrete! I have done many but always seem to struggle with getting the drain flange either too low or too high after the pour! Similarly, I recently purchase a 200 year old church that we are going to rehab and turn into a signal family. The church has a poured concrete floors that I have to install a two new baths into. What can I do to prevent back flow in the basement into the showers. Do I even need be concerned?
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" What can I do to prevent back flow in the basement into the showers. Do I even need be concerned?"
Whether you need to be concerned depends on the condition of the sewer system in that area and the relative elevations.
There are different backflow prevents that can be installed in the sewer line.
I happened to notice that the one of the area subburbs has a requirement based on the distance to the next collector and the difference in elevation between the lowest point of the building sewer and, IIRC, the height of the manhole at that collector.
" I have done many but always seem to struggle with getting the drain flange either too low or too high after the pour! "
I am just a DIY, but I have done this twice. What I do is just install the horizontal run. Then I block of an area big enough for the trap and drain.
Then I patch the floor.
That gives me unlimited height changes and a couple of inches of space for horizontal adjustments for the final location.
Thanks Bill for the insight! Maybe I should have told you that this is going to be a ceramic floor shower base so I can't leave a hole to size up later! Any suggestions with more info!
I have only done this with FG showers and I have never done a tile so I don't really know the details.But on the last one that I did after I got the walls and knew the exact location I then installed the trap and then filled in the area with concreteMy guess is that with a tile shower the height is determined by the sloped base. If that is the case them after you determine the height you need to be kept working the base to see that it come out at the right height.
Edited 2/12/2005 3:23 pm ET by Bill Hartmann
Go to a plumbing supply store, no big boxes, and ask them for a drain/ trap assembly for a motar base tile application. It will have a screw adjustable flang/strainer.
You set the stub to as close to finish motar bed height as possible. The strainer assembly screws down into the stub and will give you up to about 1" of adjustment. The same thing can be used on membrian and thinset jobs.
Dave
JulianS,
The concern about the backflow prevention device was well covered by Bill but to recap if the rim elevation of the closest downstream manhole is higher than the finished floor elevation in your house it is in your best interest to install a backflow prevention device or commonly called a "back water valve". This valve is typically installed on your side of the right of way.
With respect to your shower drain I'm sure you have the horizontal location figured out. To get the elevation of the concrete set the drain at this elevation and 24 hours after the pour screw the drain up approx. 3/8" to account for the tile. I have found that placing general purpose wheel bearing grease on the threads allows you to screw the drain up to the correct elevation after you pour the concrete. Also if you screw the drain up after 24 hours after the pour when the concrete is still green it is easy to chip the concrete out if this is necessary.
Good luck,
Clark