I beam in the way of P Trap

[Hdmstng]

Hi All,

Converting our old tub/shower to a walk in shower and the plan was to move the new 2" drain to the center. Unfortunately there is a steel I beam in the way (red outline in the first picture). The second picture shows where the trap would go if it was dead center in the shower and the third picture would be if I moved the drain back about 10 inches to the other side of the i beam. The shower is 60 inches wide, so it wouldn't be that far off center but would look a bit weird. The shower pan is going to be a mud deck pan with a Kerdi drain, so moving it back shouldn't be much of an issue, granted this will be my first mud deck pan.

In doing research on the forum, I've read that you don't want a horizontal run before the p trap due to the potential of material buildup causing smells to waft up. Could I use a 45 degree out of the drain, a short section, then another 45 into the trap like in the drawing?

Would prefer the drain in the center, but I have a greater preference for having the plumbing done correctly, so if the best and most correct way is moving the drain, then that's what I'll do.

On a side note, I picked out a trap that had a threaded cleanout on it, should I use that or get one without?

Thanks again!
HD

 

[James Henry]

45 degrees is considered vertical. I would go for it.

 

[Sponsor]

 

[LLigetfa]

I've read that you don't want a horizontal run before the p trap due to the potential of material buildup causing smells to waft up.

My shower drain is vertical and it still builds up with smelly material. I have to run a brush down it periodically to clean it out.

The 45 offset will still allow a brush to go down.

 

[John Gayewski]

I wouldn't get a cleanout trap. No real reason for them that I can think of.

 

[Jeff H Young]

the 45s are ok but so is your first pi8cture that shows swinging the ptrap that's even better I think. as for cleanout trap I don't use them but if I had one I'd use it unless i could return it not really worth the bother to return it though

 

[WorthFlorida]

Another option is a linear shower drain. One can be place on the left wall side and it be right on top of the waste line. There are many lengths, grates styles and in different finishes. Gives a clean modern look.

 

[wwhitney]

the 45s are ok but so is your first pi8cture that shows swinging the ptrap thats even better I think.

Yes, this.

ptrap2.jpg has the trap weir above the top of the I-beam--if that height works for you and the trap weir rule, it's definitely best. ptrap4.jpg should only be considered if the trap weir has to be below the top of the I-beam.

Cheers, Wayne

 

[Hdmstng]

Yes, this.

ptrap2.jpg has the trap weir above the top of the I-beam--if that height works for you and the trap weir rule, it's definitely best. ptrap4.jpg should only be considered if the trap weir has to be below the top of the I-beam.

Cheers, Wayne

First off, thanks to you and everyone else taking the time to reply!

I'm still working my head through the "weir trap rule" but I believe it would be violated based on where the 2" drain ends. The tub that was originally there drained to the left and was a 1 1/2" line that drained into a 3x3x3x1.5 which I changed out to a 3x3x3x2 to accommodate the 2" shower drain. But as you can see, the 2" line is below the floor joist that is sitting on the I beam. The I beam does have a 2x6 that is flat and I think I could remove a section of the wood to get the outlet of the trap lower by the 2x thickness, but even then I think the weir may still be a tad too high.

 

[wwhitney]

If you are committed to the height and configuration in your photo, then for the ptrap2.jpg configuration you would need to compare the following two elevations, say using a laser level:

a) The lowest you can make the trap weir with the trap on the far side of the I-beam--likely the top of the I-beam plus 3/16" for the wall thickness of the 2" PVC pipe plus maybe 1/4" for the travel over the I-beam.

b) The elevation of the top inside of the san-tee side inlet opening into the 3" barrel--that would be the top of the pipe right at the hub, less 3/16" for the wall thickness, less some amount for the curvature of the san-tee (not sure how much, you'd need to check the fitting).

Cheers, Wayne

 

[Jeff H Young]

come up with a 90 inthe wall then put a 2 x1/12 x2 spigot santee (or regular) whichever give you the height of cource then connect the vents

 

[Hdmstng]

If you are committed to the height and configuration in your photo, then for the ptrap2.jpg configuration you would need to compare the following two elevations, say using a laser level:

a) The lowest you can make the trap weir with the trap on the far side of the I-beam--likely the top of the I-beam plus 3/16" for the wall thickness of the 2" PVC pipe plus maybe 1/4" for the travel over the I-beam.

b) The elevation of the top inside of the san-tee side inlet opening into the 3" barrel--that would be the top of the pipe right at the hub, less 3/16" for the wall thickness, less some amount for the curvature of the san-tee (not sure how much, you'd need to check the fitting).

Cheers, Wayne

What I'm hearing is I have another opportunity to use my new laser level! Will get the measurements and see how everything lines up!

 

[Terry]

I would have dropped the toilet in downstream with a wye and a 45. Combo would also work.
The santee then could have been a 3x2 for the tub only.
I would have drilled the 2x10 joists and run the trap arm through them, thus allowing a long turn 90 below the 3x2 santee.

 

[Jeff H Young]

I like Terry's idea better but Looks like your already glued up and why replace the toilet flange and closet bend . I'd prefer to not rip it all out. or better yet just put those 2 45s on the shower drain tailpiece and call it good

 

[Hdmstng]

Thanks for all the help. Got a little side tracked with spring break (have two young ones) but finally got back to the bathroom. Was able to get the laser level setup to check the height of the vent/trap weir and the trap will be too high due to the I-beam. Even cutting out the wood on top of the I-beam, it still would fail the weir/trap rule. Will either use the 45's to keep the drain centered, or shift it back about 10 inches and adjust my mud deck. Thinking of the latter since it would 'hide' the drain from view when looking into the shower.

Once again, thanks for all the help and advice, very much appreciated!

 

[Jeff H Young]

doesn't look too challenging I cant tell exactly what's going on or what the laser is depicting just gotta get over the beam. Like I posted I was thinking under the joists up the wall with vent by the water lines with santee pointed toward shower drain you'll be in the joists bay.

 

[Hdmstng]

I would have dropped the toilet in downstream with a wye and a 45. Combo would also work.
The santee then could have been a 3x2 for the tub only.
I would have drilled the 2x10 joists and run the trap arm through them, thus allowing a long turn 90 below the 3x2 santee.

I'm considering making those changes, especially as I wasn't able to snake through the 180 degree bend from the toilet flange. Would it make sense to add the combo pictured below up to the 3x2 santee and vent for a clean out?

A quick question though, if that main line is backed up, aren't you going to have a giant mess when you open up that threaded cleanout? Granted you can't take care of any water trapped in the vertical pipes, but would adding a 45 and raising the cleanout opening at least above the horizontal make sense? At least then you minimize the amount of waste that can come out.

 

[Reach4]

In warm areas, it seems fairly common to extend the cleanout through the wall to outdoors. I don't know if that would work so well in cold areas.

The other thing is that clogs are often partial, and given time, the clogged pipe drains.

 

[Hdmstng]

Ran into one additional issue, the distance from trap to vent is over 5' if I go straight out and turn 90 to the trap. Is it wrong to use a couple of 45s through a joist to run the 2 inch drain diagonally? Would need at most to go through two joists like that. Is it okay to do or any watch outs?

Side note, 3 inch holes and the 2x10 in the picture was just a practice drill. I know 3.25 inch is max dia and 2 inches from top or bottom of joist.

 

[wwhitney]

On the 45s through the joists, if the hole diameter ends up under 1/3 the joist height, and the hole is at least 2" from the top and bottom of the joist, that's OK. If the hole diameter needs to be bigger than 1/3 the joist height, then the joist will need reinforcing.

On the 5', that's not a limit under the IPC, which I believe Ohio uses. The basic rule is that the trap arm can't fall more than one pipe diameter. So for a 2" trap, the trap arm could fall 2", and the trap to vent could be up to 8', if you get the trap arm slope perfect. Of course, where the resulting holes have to be in the joists is also an issue, since they need to be 2" clear from the top and bottom of the joist.

Cheers, Wayne

 

[Hdmstng]

Went ahead and followed the advice from Terry and others to have the toilet waste go straight down. While I did have some play with the main line laterally, I had to use a Fernco fitting to join the two wyes together. Added the two hangers as I needed to get the proper 1/8" per foot drop. Left of the Fernco is perfect at 1/8, the right side drops at 1/4".

Will finish the 2 inch lines for the shower drain tomorrow and have the 1/4" slope there as well. Did find that the sink drain was either back pitched this entire time or when installing the sanitary tee I pushed it up. Will remove the Fernco on it and trim down a bit so the pitch is correct.

Oh, the plumbing goes through the HVAC return duct. That duct also serves as the return for the room on the other side of the wall as well as the bedroom on the floor above. Needless to say, the bedroom above's return duct has insufficient vacuum.

Thanks again for all your help and advice!