Discussion Forum
Hello all,
In my master bathroom, I am replacing a bathtub with a shower base. The bathtub had 1 1/2″ drain lines (ABS) and the shower base manufacturer specifies 2″. I have full access from the basement, so I figured, no problem and I replaced the 1 1/2″ line with 2″.
It all looked terrific, but after it was all glued together, I noticed I forgot the P-trap!! The fittings coming out of the shower base are a couple of street 45’s, so I can’t easily cut in right below the drain.
My question is…Do I have to install the trap directly under the drain, or can I install it “inline” 10″ or so along the pipe?
Thanks in advance for any advice anyone can offer.
Discussion Forum
Up Next
Video Shorts
Featured Story
The best tool for straight, splinter-free cuts is made even better without a cord.
Featured Video
How to Install Exterior Window TrimHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
If you just glued this up you can remove those fittings -- the glue remains soft for about 24 hours.
Sometimes you have to cut the pipe out from the inside, but often just wiggling the pipe will work it loose.
Thanks Dan, but it has been a few days since I glued it up and it is rock solid. Can the trap be further down the line, or do I have to chip out the 45 street fitting and start again?
Thanks!
There are some circumstances where it can be further down the line, but I don't know what those are.
10" fine, just make sure
10" fine, just make sure there is a vent downstream.
Yeah, the most important thing is to have the vent tee within about two feet of the trap.
P-trap
The purpose onf the p-trap is to block sewer gases from venting through the shower or bath drain. Putting 10" away from the drain should not impede that function as long a proper vent is installed on the downstream side of the trap (generally required to be within 3' of the trap). Think of a large commercial double bowl sink with long cross over waste arms going to a single trap. Both sinks drain properly even though both drains are more tha 10" away from the single p-trap.
The sink is a good analogy for more than just that reason. My double sink has more than a 10" run to the single trap which is functional but..............
Crap collects on the sides of both those "untrapped" sections and it inevitably stinks. I probably disassemble the thing 6 times a year to clean out the untrapped sections and inbetween times we have to dump baking soda/vinager down them.
Now a shower doesn't have the food scraps like a sink but I am just mentioning that you are setting up a larger section of pipe where its always wet and dark which is a combination for nasty stuff (and stinky) to grow.
Just think about how nasty the pipe smells when you have to deal with one downstream of a trap and thats what you will eventually get in the untrapped section.
Thanks everyone for your guidance. I think I understand, but I have posted a drawing (sorry, its a bit crude) of what I have and what I think I need. Can you kind folks take a look and let me know if I'm on the right track???
Thanks yet again!
Not such a bad drawing--and that arrangement will work to keep sewer gas out and to protect the trap from being siphoned by the drainage of other fixtures downstream.
The installation you will have is called a "running trap"--i.e., the trap inlet and outlet are both in the horizontal and at the same level. Running traps are subject to more frequent clogging because they greatly slow the flow compared to when the inlet of the trap is in the vertical, since the velocity of the vertical drain helps flush the dip of the trap.
On a shower, however, I doubt you will have much trouble. Not like a kitchen sink where you're draining a lot of grease, oil, scraps, etc.
Thanks!
@rdesigns...
Fantastic explaination, thanks very much. I am very relieved that I don't have to cut apart the fittings. Thanks again to you and all of the posters.
Jake
Since you have full access and are using a "running trap" it might be a good idea to make sure you have a cleanout on that new trap
"just in case".
Geoff