Need advice on plumbing a new home

[jim garvey]

Hello,
I ended up needing to plumb my outside wall and ran into a issue with the crawl space blocks being in the way. I am attempting to follow a diagram Terry has here and it seemed to be going well until I got into the crawl space. Because of lack of room under the wall I’m attempting to 90 the bottom fittings away from the wall. I tried to make some pictures to show what I have done on the first level and what I think I need to do in the crawl space. I could and would appreciate any advice on if what I’m doing will pass code. The pictures should explain better what I’m up to.

 

[wwhitney]

Looking at just your last drawing, I understand that the san-tees on their back that you have marked with a red X are to be changed to combos, as they need to be. Please label all the vertical pipes you've drawn in at the top of the picture with their intended purpose.

A couple preliminary comments: for a jog in a vertical pipe (as in this case to presumably get further away from the exterior surface of the wall because the block foundation is thicker than the wood frame wall) the use of two 45s for the jog is better in all cases than the use of two 90s, and depending on the pipe's role, may be required.

How is the shower drain going to be vented? If the intention is the upper left pipe is a dry vent for it, your configuration doesn't work. What would work in that case is to use a san-tee instead of a combo, then two 45s to jog the dry vent into the wall (90s not allowed here, the vent can't go flat below the flood rim of the shower). And of course, the total fall in the 2" trap arm from the trap outlet to the san-tee would need to be no more than 2".

Cheers, Wayne

 

[Sponsor]

 

[jim garvey]

The pipes going up are the same as Terry’s drawing from left to right. I don’t have the far right one in yet.

From left to right on the picture:
Far left will vent the downstairs tub (I wrote 2” long wye to shower but it is the bathtub)
Second from left should vent the toilet, upstairs shower and sink
Third from left vents the downstairs toilet
Forth one vents the downstairs sink.

Should to be basically exactly like Terry’s image. Problem is the offset I now need. Is it okay to use the long 90 to turn the main pipe towards the septic or sewer. I will get the 45’s for the bottom and probably for the turn under the wall also, was not sure whether a long 90 or 2/45’s was better.

 

[jim garvey]

Do you mean the long 90 should be 45s to the tub.? Then double 45s up from the crawl area.

 

[wwhitney]

I think you are trying to say (changes bolded, my comments in parentheses)

From left to right on the picture:
Far left will vent the downstairs tub (then the comments in the last paragraph of my previous post apply)
Second from left would drain the toilet, upstairs shower and sink
Third from left vents the downstairs toilet (then again the jog in the dry vent must be done with 45s, and the fitting hidden behind the closet bend should be a sanitary tee edit: not required for a WC)
Fourth one drains the downstairs sink.

Cheers, Wayne

 

[wwhitney]

Do you mean the long 90 should be 45s to the tub.? Then double 45s up from the crawl area.

I think we have a terminological difference here. The fitting you are calling "long wye" I would call a combo; it is also called a wye plus 45, and you can make it out of those two pieces, a wye and a street 45. Since it's more of a tee than a wye, I wouldn't call it a long wye.

So the combo on the left side of the picture needs to be a san-tee, not a combo. And the dry vent above that combo needs to jog into the wood wall using two 45s, not two 90s.

Cheers, Wayne

 

[jim garvey]

I appreciate the help, I’m a rooking! I think the plumbing is the hardest part of building the house so far. The bottom fittings in the picture are not glued I had to build them like that to just keep a picture in my head of how I thought it may need to be. I will check the upstairs shower and use 45s up there also cuz I think I used a 90. I will take and use all your advice and see if I can get it done. Thank you!!!

 

[Jeff H Young]

that drawing is a good instructional , for the concept but in practice running diagonal through walls is not often desirable would have been a disaster on a 2x4 wall which isn't uncommon. seems on track though

 

[jim garvey]

Okay, quick question. I have used all 2” for the vents and live in Michigan. Will I need to switch some to 1 1/2 PVC.

 

[Terry]

Okay, quick question. I have used all 2” for the vents and live in Michigan. Will I need to switch some to 1 1/2 PVC.

2" vents are better than 1.5"

 

[jim garvey]

Could I do something like this in the crawl to keep the pipe as close to the joist as possible. Looks like my original plan is going to make my main pipe real low on the septic side of the house where it will exit out.

 

[Reach4]

3 inch and 4 inch can slope as shallow as 1/8 inch/ft under IPC.

A laser level can be handy.

 

[jim garvey]

I will keep to the 1/8 per foot slope that will help some. Do you think the drawing will pass code?

 

[wwhitney]

Seems like that layout would only save you maybe 6" because the 3" line could start up in the joists. But if you need those 6", you can make something like that work. Edit: I don't see how that will actually save much height, maybe 1" or 2" for a more direct route to the septic. But the 3" line still has to be below the joists for all those wyes coming in below the joists.

Where are the upstairs shower and sink drains? All you show is the upstairs WC.

The little drawing in the lower left has the san-tee on its back oriented backwards. And you're better off using a combo there, unless you need to use a san-tee on its back to save some height. [UPC requires a combo; the IPC would allow the san-tee on its back.]

The main tricky geometry would be ensure the tub vent stays no more than 45 degrees off plumb as it rises from the drain up into the wall. So it might be easier to point the tub trap outlet parallel to the wall (assuming it's under the wall already), and then just use a 45 after the vent takeoff to point towards the wye on the main 3" line.

Cheers, Wayne

 

[jim garvey]

Those drains come down the combos in the wall picture to the 3 inch pipe that also drains the upstairs toilet. I have to get out there and look at it in person, I live 90 minutes away from there. Seems my original idea may start at about 15” on that end and after 40 ft it would be at least 5” more so it may be to much.

 

[Jeff H Young]

jim garvy you are changing things , the upstairs toilet moved, and made other changes but yes it works its not real detailed and make sure you use correct fittings btw the new drawing is way higher but your the one on the jobsite I dont see a depth issue . are the bottom of your joists in the dirt?

 

[Reach4]

I suspect your drawing is OK. If you could join the upstairs waste downstream of where the shower joins, you would not need the toilet vent.

 

[jim garvey]

The upstairs is exactly the same as Terry’s diagram. The downstairs toilet changed so it will allow me to use less space in the crawl.