Shower drain size going from tub to shower

[Bid19123]

I have just started the demolition work to replace a nasty old tub with a walk in shower. Found some surprises under the tub. For some reason it had been packed in with old clothes; not nice. Also the tub was to small for the alcove space so the walls at the lower 2 feet had been mortared out at 45 degrees. Biggest surprise was the drain; it sits in a sand filled hole. After removing some of the sand to expose the pipe I came across a black cable which I think may be an electrical line; I am a little scared to continue. The main problem is the drain is only 1.5 inches and I stupidly purchased a 2 inch drain for the shower. What are the available options to resolve this? The drain pipe is under a concrete foundation so I cant replace it to 2 inch pipe. Can I reduce the drain I purchased down to 1.5 inches. I am scared this may cause a problem later down the line. One last question; How is the hot and cold water pipe normally run in a concrete block house. I hoped it would run under the floor from the adjacent bathroom but I cant find any sign of it

 

[Terry]

Showers will work with 1-1/2" drains. I normally using a reducing coupling from 2" to 1.5" on the vertical below the drain and above the p-trap.

If it's new work, then always 2".

 

[Sponsor]

 

[Bid19123]

Thanks Terry. I will do that. No sign of a p trap just a 1.5 inch pipe heading down into the sand. I plan to run a 90 degree bend of this in order to center the drain in the shower pan. Should I add a p trap or work on the assumption that either one is already there deeper under the sand or if it never had one before it doesnt need one now!

 

[Terry]

You need to see if it has one. If not, you must add one. Otherwise, you will have sewer gas and smells from the septic tank.
Now is the time to make sure you have prevented sewer smell in your bathroom.

 

[Bid19123]

Your the man! Thanks Terry

 

[Cacher_Chick]

If you pour water into the drain and can see the waterline by looking down the riser, that is because a trap is retaining it.

You can use a shop vac to suck the sand out of the hole. An existing trap will need to be removed and the drain reworked so the trap is located under the new shower drain.

 

[Jadnashua]

IF it literally just drains into the sand, that's a poor situation and should be resolved. A p-trap also needs a vent line or it can siphon dry.