I am remodeling a bathroom and am re-routing some drain lines. I have a single story home with a crawl space beneath. The drain from the old shower ran between two floor joists. Where I have the new shower the drain line will have to cross 3 joists...My question, is it ok to run the drain line under the joists, or is it better to drill holes. If I run it below the joists I can use one piece of pipe. If I drill through the joists I have to use couplings, and offset the holes to get the 1/8" per foot drop for grade. The new shower will have a 2" drain vs 1.5 from the old shower. I also plan on tying into the former vent. I've attached a picture to help explain. The drawing only shows two joist, I didn't want to redo the drawing.
drain lines
- Thread starter vskerche
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Doherty Plumbing
Journeyman & Gas Fitter
You are better off NOT drilling through the joists. Run then drainage under the joists. Just make sure you support it properly!
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Gary Swart
In the Trades
If I read you diagram correctly, you are planning to reduce the 2" drain to 1-1/2". That is a major no-no. You can never reduce a drain line. It has to remain the same or get larger.
Drain line reduction
See the pic below showing the drain line reduction plan. The previous pictures show an overhead view of the drain set up, this pic would be as if you were looking at the lines while standing between the joists. The new 2" line is below the joists based on the reply that it would be better to do that than drill holes in the joists. BTW..should I insulate the drain line? The reason I am going with a 2" line is the shower pan has a 3" off-set strainer, and has a 2" connection..I couldn't find an offset drain with a 1.5" connection. If anyone knows where I can find a 1.5" off-set drain let me know and I'll go with that.
See the pic below showing the drain line reduction plan. The previous pictures show an overhead view of the drain set up, this pic would be as if you were looking at the lines while standing between the joists. The new 2" line is below the joists based on the reply that it would be better to do that than drill holes in the joists. BTW..should I insulate the drain line? The reason I am going with a 2" line is the shower pan has a 3" off-set strainer, and has a 2" connection..I couldn't find an offset drain with a 1.5" connection. If anyone knows where I can find a 1.5" off-set drain let me know and I'll go with that.
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the plan
Ok after reviewing the replies, and looking at my plan here is what I decided to do. Since the shower pan drain is an Oatey 103 series offset, and calls for 2" drain, and a previous post say's not to reduce the line, I am going to reduce from 2 to 1.5 right out of the drain (Prior to p-trap) see pic, and run 1.5 all the way out. Instead of the double bend I have shown in my 2nd pic above, I am going to run the line far enough below the joists so that I can put in one 90 and drop to the 3" line out.
Ok after reviewing the replies, and looking at my plan here is what I decided to do. Since the shower pan drain is an Oatey 103 series offset, and calls for 2" drain, and a previous post say's not to reduce the line, I am going to reduce from 2 to 1.5 right out of the drain (Prior to p-trap) see pic, and run 1.5 all the way out. Instead of the double bend I have shown in my 2nd pic above, I am going to run the line far enough below the joists so that I can put in one 90 and drop to the 3" line out.
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Doherty Plumbing
Journeyman & Gas Fitter
You are allowed to bush down from 2" to 1.5" right at the shower base. And don't use a 90... use two 45s.
Gary Swart
In the Trades
As a DIYer, I really hesitate to disagree with a true professional, but I'm going to do so this time. I seems to me that no matter where you reduce the size, you are violating the cardinal rule that says never reduce a drain, and you will be making a 1-1/2" shower drain. It will certain work, but I can't believe it will pass code inspection. As far as insulating drains, it would serve no purpose. A drain line never has water in it except when actually in use.
Doherty Plumbing
Journeyman & Gas Fitter
Well up here in Canada you would be wrong in assuming this would not pass inspection because the tailpiece is NOT considered part of the drainage system (silly I know right) but the drainage system starts at the trap.
You are most certainly allowed to bush down a 2" shower drain to 1.5". BEFORE the trap ofcourse.
Your code will be different but this is from the Canadian National code...
2.4.9.1 No Reduction in size
1. A soil-or-waste pipe shall be of a size not less than the size of
(A) A vent pipe that is connected to it, or
(B) the largest soil-or-waste pipe that drains in to it.
So therefor you aren't reducing a soil-or-waste pipe you are reducing the fixture's waste opening. And in the Canadian code you will not find anything that says you can't reduce a fixtures waste opening....
In fact it is done ALL the time. Hardly anyone runs a 2" drain off the shower unless you are forced to use 2" because venting issues. Showers come with 2" waste openings to give you the option of running 2" or 1.5" with ease. Not because you HAVE to run 2".
I have never had a shower turned down because of doing this....
Also don't forget that EVERYTHING in the code book could be over written by the authority having jurisdiction, IE the inspector. If the inspector says you can run your drainage up hill and reduce in size and not vent anything you're legally allowed to do this. They have all the power in determining how to interpret the code book. If they say "do this or that" you'll have a tough time arguing your case even if the code book says different. And yes it's right in the code book saying the authority having jurisdiction has the final say.
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Another option
Ok here I go with another option...Below is a picture of how/where the 1.5" line is attached to the 3" line (3x3x2 wye)...There is a insert in the 2" portion of the wye that accomodates the 1.5" pipe...How difficult would it be to clean that insert out and go with 2" pipe
Ok here I go with another option...Below is a picture of how/where the 1.5" line is attached to the 3" line (3x3x2 wye)...There is a insert in the 2" portion of the wye that accomodates the 1.5" pipe...How difficult would it be to clean that insert out and go with 2" pipe
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Doherty Plumbing
Journeyman & Gas Fitter
Ok let me get this straight....
are you planning on running water through that 1.5" line you're referring to in the picture? If so you need to cut out that 3x2 tee and replace it with a 3x2 wye and a 2" 45. Then it would be really easy to run 2"
Well, since it is the wrong fitting there, cut it out and use a 3x2 wye or combo fitting.
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Fitting
That is a wye, 2" on top...How difficult is it to open up the 2" part (remove the reducer)...if can't be accomplished without cutting out whole wye, then I will reduce to 1.5" at shower drain, and run 1.5" throughout
That is a wye, 2" on top...How difficult is it to open up the 2" part (remove the reducer)...if can't be accomplished without cutting out whole wye, then I will reduce to 1.5" at shower drain, and run 1.5" throughout
Doherty Plumbing
Journeyman & Gas Fitter
Nope, it's a 3x2 Sanitary Tee not a 3x2 wye. You need to make it a wye. It's the wrong fitting.
Doherty Plumbing
Journeyman & Gas Fitter
The picture isn't fuzzy at all. If it passed inspection originally that doesn't mean it's the proper way to do things. Inspectors are usually guys who have taken a 1 week course on everything in a building and know nothing about anything.
To do it properly you need to replace the entire fitting.
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Not to be a smart $%^& but again if it was approved originally 20+ years ago(and its worked that long) I'm not going to take out 40+ feet of pipe to change it. I say 40+ feet because the pipe is fixed at both ends, so if I cut the TEE out to put in a wye, I'll need to take all the pipe out and build the line up from scratch. I really don't see a big problem..about 2 feet to the right of that tee is a 90 elbow that is the vent stack...so even if the flow into that tee goes the wrong way, it will eventually drain down to the left. I'm borderline OCD (LOL) so i may just cut the whole line out and redo it because now it will bug me...
If you want dumb answers, then don't ask here.
That's what Home Depot is for.
They don't have plumbers working the isle.
They hire kids from high school.
If you ask a plumber how to do it right, then don't be upset.
We're not telling you you have to do it, or that we care if you do it.
It's your home.
I wouldn't plumb my home that way, or a customers home that way.
I wouldn't plumb it that way in Guatemala either.
With 40' of pipe, it's not hard to slip a new fitting in.
Heck, all you do is drop it down a bit and then lift it up.
It takes any plumber no time at all.
It's not like it's rocket science.
And if worse comes to worse, you can always use a shielded coupling on one side.
That's what Home Depot is for.
They don't have plumbers working the isle.
They hire kids from high school.
If you ask a plumber how to do it right, then don't be upset.
We're not telling you you have to do it, or that we care if you do it.
It's your home.
I wouldn't plumb my home that way, or a customers home that way.
I wouldn't plumb it that way in Guatemala either.
With 40' of pipe, it's not hard to slip a new fitting in.
Heck, all you do is drop it down a bit and then lift it up.
It takes any plumber no time at all.
It's not like it's rocket science.
And if worse comes to worse, you can always use a shielded coupling on one side.
apologies
Terry...didn't mean to sound like a smart $%#@...I love these forums..there are a lot of knowledgeable people out here and I appreciate all the time they (you) put in to answering our questions...my favorite DIY show is Holmes on Homes..that guy does it right no matter what..and my dad always told me "If you're going to do something, do it right the first time...because if you don't have the time to do it right, when are you going to find the time to fix it"
I'll post some more pics in the next day or two showing the set up, and what I plan to do..
Terry...didn't mean to sound like a smart $%#@...I love these forums..there are a lot of knowledgeable people out here and I appreciate all the time they (you) put in to answering our questions...my favorite DIY show is Holmes on Homes..that guy does it right no matter what..and my dad always told me "If you're going to do something, do it right the first time...because if you don't have the time to do it right, when are you going to find the time to fix it"
I'll post some more pics in the next day or two showing the set up, and what I plan to do..
Current Set-up and plan
Ok folks here it is...First a few pictures showing what the original plumber did to some of the floor joists(about 1" of joist left after cutting out for plumbing). The next pictures show the current plumbing under the house. The capped 3" line is where the toilet in the bath I am remodeling drained to. Per the advice from Terry and others here, I am changing the Tee(3x3x2) to a wye(3x3x2), all other PVC fittings will remain the same. The next picture gives an overhead view of the current orientation of the TEE that both toilets drain to, and then how I plan to reconfigure. The reason for the reconfig is that I am moving the toilet in the remodeled bath from its original location. To prevent a long winding drain, the reconfig will give me a straighter shot. The current drain in the master bath will have to be re-plumbed, and there will be a few turns in it, but nothing that would happer drainage.
Please let me know if anyone has any suggestions or comments. Currently working on incoming water lines so I've got a few days before I tackle the drainage
Ok folks here it is...First a few pictures showing what the original plumber did to some of the floor joists(about 1" of joist left after cutting out for plumbing). The next pictures show the current plumbing under the house. The capped 3" line is where the toilet in the bath I am remodeling drained to. Per the advice from Terry and others here, I am changing the Tee(3x3x2) to a wye(3x3x2), all other PVC fittings will remain the same. The next picture gives an overhead view of the current orientation of the TEE that both toilets drain to, and then how I plan to reconfigure. The reason for the reconfig is that I am moving the toilet in the remodeled bath from its original location. To prevent a long winding drain, the reconfig will give me a straighter shot. The current drain in the master bath will have to be re-plumbed, and there will be a few turns in it, but nothing that would happer drainage.
Please let me know if anyone has any suggestions or comments. Currently working on incoming water lines so I've got a few days before I tackle the drainage
Attachments
Doherty Plumbing
Journeyman & Gas Fitter
I have no new advice for you but just follow the advice we've already given you and you should be fine!
Good luck with it.
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