Move drain over 13” in Shower

[Susan Harris]

I am enlarging a shower and need to move the drain over 13 inches. Concrete has been busted up and hole dug down 17” beside the drainpipe. The ptrap is still under the ground. Can I put a 45 elbow on existing pipe, then PVC then another 45 then PVC to relocate the drain? I have attached 2 drawings to explain. Thanks in advance for your answer!

 

[Jadnashua]

You should move the p-trap so the riser is right over the p-trap. As long as you can maintain at least the minimum 1/4"/foot slope, it should be okay with one possible gotcha...the vent must be NGT 60" from the outlet of the trap. How far away will the vent be if you move things?

Having a long, jointed riser means more surface area that could accumulate crud and smell. A vertical riser to the trap tends to scour cleaner, and then the trap right below with its water seal will block anything beyond from smelling up the place.

Once you resolve that, suggest you check out www.johnbridge.com for help in constructing your shower. There's a huge amount of just plain wrong info out there and 70-80% of tiled showers built in this country are not done according to industry standards. There are lots of different methods, none are particularly hard, but very detail oriented...mess up one requirement, less than optimal operation. The industry bible is the TCNA handbook that gets updated annually. That's the 'Tile Council of North America'.

 

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[Susan Harris]

Vent is within 3 feet of existing riser, so moving drain 13 inches keeps it within the 60 inches max. But looks like I may need to keep digging, so ptrap is directly under riser. Am I understading your best scenario? Would it be within code to do as I drew it?

 

[Jadnashua]

There's an issue with the height versus the p-trap in that gravity accelerates things and could run past the trap leaving it ultimately not filled all of the time. I do not know the specifics. Assuming that your existing one was okay (not sure that's true!), since the overall height won't be changing, it probably will be okay. From a best practices viewpoint, it won't be.

 

[Cacher_Chick]

You can cut off the existing trap and use 45's to offset the location of the new trap. The offset can be horizontal only, as you cannot alter the overall pitch between the trap and the vent.

 

[Susan Harris]

Ended up with this! Thanks for all the replies!