Teardrops n Tiny Travel Trailers

I bought a Lyons fiberglass 32x24 RH drain tub with 2" opening. I then ordered a JR 2" drain which has a 1 3/4" threaded end..
(I also have the Hepvo trap with 1 1/2" 'shoe' on it that fits this perfect..

There is only about 1 1/2" of threading length on it.. and the tub has runners molded in for drain angle and support..

The drain threads are just under 2" and I tested a 2 1/8" hole saw and that gives me a bit of wiggle room before the threads would hit my 3/4" Drymax floor..

The question is.. do I thread the drain to the tub only?? or the tub and the sub-floor as 1 item using the drain to hold it all together??

All the pics online I've found show the drain attached to the tub/showerpan and just a larger hole thru the subfloor and usually outside under the RV is the drain threads and swivel P-trap adapter..

The tub recommends keeping the HOLE small under the tub to try and support the drain area and said something about plumbers putty..??

If my mental picture of your setup is correct, I suspect that if you did not set the trap fitting tight against the tub threads, then you run the risk for leaks occurring.

The hole should be just a little bigger. Attached to the pan, not the floor. As far as I know about plumbers putty is work some into the threads to prevent leaks.
I do not know what your shower pan looks like. If you were to picture where the weight will be taking a shower. Is the pan sitting on the floor or is it raised off the floor. If it's off the floor something needs to be placed between pan and floor for support.

It's got supports built into the bottom of the tub. They are very rigid.

Like 1/2" high and 1" apart under the tub.

So drill a bigger hole and let the 'tail' of the drain dangle correct. Then trap with Hepvo.

On page nine of my posts,
viewtopic.php?f=42&t=61777&start=120

See my shower pan setup. I did not use a Hepov, but nevertheless, drilled the hole larger.

The plumbers putty goes on the inside of the pan drain flange. In other words it will seal your drain flange to the pan on the top side you stand on. Take a golf ball size slug of it and roll it out into a weenie shape, then wrap it all the way around your drain piece that goes on top, no voids, you will have flange, putty then shower pan. Tighten it up to the pan as required and the excess putty will ooze out around the flange, it then peels right off. Hope this helps

What Redneck about the plumbers putty around the drain flange where it seats in the tub/shower pan. You will also have a washer and lock nut on the underside of the pan to secure the drain. As for hole size in the floor you are going to have to attach the Hepvo after you put the pan in place so leave enough room the tighten the threaded fitting where the Hepvo attaches to the drain. Use Teflon Pipe Tape on the threads of the Hepvo fittings.

Duh, I wasn't thinking inside the pan. So top 2 post are right. It's odd about the Teflon tape - I was told not to use it in drain pipe. Or actually to avoid using it and use the putty.

Not sure if you will have a trap on your shower or not. If so, and you use a mechanical joint trap (the one with slip-nuts, nylon taper washers and threads) another old plumbers trick to seal it properly is to again take a little plumbers putty about the size of a .22 slug and put it in 3 different points inside the slip-nut female thread part as you assemble the trap. Again the excess will ooze out the top of the nut as you tighten it and then peel right off...........do this properly and it will not leak. And remember when buying your trap you will always need at least 1 and possibly 2 extra slip-nuts and washers depending on install method. Again I hope I was of help.

For what is worth, I am not using a trap for my shower water.
With this drain mechanism shown, I am going to drain my shower water into a 5 gal container and dump it later.
Therefore I can get away with no trap.
Just thought I woud throw out another option for you to consider. And with this drain, I can put/ bend a low point in it to act like a trap.

That's what I have for my sink and shower. My test shower and washing dishes went well. I don't think a trap is needed for flow but for odor. For a weekend or a few days the grey water shouldn't get to bad. I'm planning on letting it run on ground where allowed too.

Padilen wrote: I don't think a trap is needed for flow but for odor.

You are correct, a trap is a seal for odors, nothing more, nothing less.