Why 2" drain for shower

[Geniescience]

hi FJK

just for the record, i'll say I probably spoke too casually in my post far far above where i named DIY folk instead of speaking more precisely; (then again, it maight not have helped to name all the other categories like handymen etc. )

As you and I just corresponded on another thread, about two traps in series (not doing it) and about (not) reducing drain pipe size in the middle of a run, I'll add here now for the record that I don't intend to represent code or the enforcers, and i do agree with the point of view that says that a few of the articles in the code are more like best practices standardized rather than true safety issues. It is hard to discuss these ones in public. We need an open discussion forum for that. That is why I came here.

No-one will give a blessing to a 1.5" pipe for a shower, but some will discuss the factors that make it work as drains are expected to work. Slopes, venting, distances, etc.

david

 

[Master Plumber Mark]

It will work ok....

it will work ok, a 1 1/2 drain for a shower..

it is just not desired ......


if all you got to work with is 1 1/2

without tearing up the whole house just to make it bigger

it will work..... the hair might or might not clog up quicker in 1 1/2


Now if you can make it 2 inch in the shower pan

and then reduce it down to 1 1/2 somewhere down the liner aways it will work....

sometimes you got to do what you got to do...

to win....

in my very own home I had a terraza 36 inch shower drain on a concrete slab since 1964 that was only an 1 1/2 drain and trap and I did no tknow it till I tore the whole thing out of the slab to install a whirlpool tub...


so it will work.

 

[Sponsor]

 

[FJK]

Sorry I haven't got back to the forum for a while.... So, given everything I've read so far, how does this all get pulled together if I replace the tub with just a shower and use a 1-1/2" drain instead of 2"?

The existing tub drain & overflow get removed, the respective t-fitting for the preceding, and finally the slightly downstream trap. Now, considering I have not seen the shower drain hardware, I assume it is designed to plumb to 2". So, coming off the drain for the shower base, what size trap is used? Then, if there is some portion of 2" off the shower base drain, when do you transision to 1-1/2"? Or, is there simply a 1-1/2" base drain you start with?

Thanks, FJK

 

[Geniescience]

this is a delicate situation here. No matter what anyone says here, the advice is all geared to doing the opposite of what Code calls for; furthermore you are a true DIY and some of your questions and descriptions show you lack some basic knowledge, not a big thing, but it makes the situation all that more delicate... So it is hard to know how to respond, in a public forum. Many reactions possible.

Some will say you shouldn't reduce a drain line at any time, so best is to go with the existing 1.5" P trap you already have in place. Others will suggest a new 2" P trap, then either a reducer or a street elbow (search on those terms) to connect into the 1.5" pipe. "Who knows?" said rhetorically is the best answer you'll get. This may be the right time to hire a Master plumber; let him make the judgement calls necessary.

david

 

[Leejosepho]

... considering I have not seen the shower drain hardware, I assume it is designed to plumb to 2". So, coming off the drain for the shower base, what size trap is used? Then, if there is some portion of 2" off the shower base drain, when do you transision to 1-1/2"? Or, is there simply a 1-1/2" base drain you start with?

If you are going to stay with you existing 1-1/2" drain line, it is not going to make any real difference how large or small anything connected to it might be. In other words, the 1-1/2" line is going to pass the water from your shower no matter how that water is directed there.

Personally, and even though I prefer the larger trap, I would use the 2" shower drain and immediately reduce to 1-1/2" (either vertically or horizontally) before going into an 1-1/2" trap and on into the drain line so you do not end up having a horizonal reduction from 2" to 1-1/2" where the larger trap would otherwise be connected to the smaller line.