Basement Bathroom plumbing and venting [Questions]

[DIYCloak]

First time poster, the forums have been great for other questions I have had in the past. Have a bit more unique situation that I can't find a good solution/verification for.

Background info: I am drawing up the plumbing for a basement bathroom (DIY) and would like to know if I have the drains and vents reasonably (read: properly) done and if there were ways to improve it.

The bathroom will have washer, shower, sink, and toilet needing to be plumbed. The configuration is partly limited and driven because of ceiling height (to meet local code for height and put the shower where there is the most head space)

The distance from the shower to the existing main is ~14' (my understanding is I need a 3.5" slope from shower to main, which will require 4" pipe). There is enough ceiling height outside of the planned shower to allow for all water lines and a vent to be brought across and still meet code for height from floor.

The plan is to bring new vent(s) up alongside the existing 3" vent, tie-in above the fixtures in the upstairs bathroom (upstairs is toilet, sink, shower/tub).

Several questions:
1) Can I vent the washer drain and shower together as drawn? (there would be enough room to vent the shower separately, but would prefer not connecting vents between/over the planned door, one vent seems easier than two there and allow to me to bring it across between two low points in the ceiling)
2) Can I transition from 2" to 4" for the drain portion from shower/washer to the existing 4"? (I know that a 3.5" slope needs 4" pipe, but unsure if I can go 2" to 4" pipe while maintaining that slope)
3) Am I properly venting the toilet and sink?
4) Suggestions for improving it overall? (saving on materials is less of a concern as much as making sure everything drains and vents properly)



Thanks!!!

 

[Reach4]

You must vent the shower before it joins the standpipe waste.

In IPC you would need 3 inch to carry the standpipe waste after it joins other waste, but in UPC, and I suspect Canada, 2 inch would be enough.

I don't know if Canada permits horizontal dry vents. UPC does but IPC does not. If you bring the shower drain over to the vertical dry vent, that would not come up.

A bathroom lavatory could provide a wet vent for a shower before the standpipe.

) Can I transition from 2" to 4" for the drain portion from shower/washer to the existing 4"? (I know that a 3.5" slope needs 4" pipe, but unsure if I can go 2" to 4" pipe while maintaining that slope)

I don't quite understand the question, and I sure don't know anything that needs a a 3.5" slope. What does that mean to you? The maximum minimum slope of anything I know is 2% (1/4 inch per foot).

If somebody knows the Ontario code and could assess your plan, that would be good. Not a lot of regular posts checking layouts on that that I remember.

3) Am I properly venting the toilet and sink?

I don't think so. If you were to join the standpipe drainage downstream of the toilet and if the sink is a bathroom sink (lavatory). and putting the toilet drainage after the lavatory drainage, that may be the only changes you need. At least in US codes, adding the non-bathroom drainage into the mix interrupts the bathroom wet vent rules. I know Canada is more permissive in some points.

 

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[DIYCloak]

You must vent the shower before it joins the standpipe waste.

In IPC you would need 3 inch to carry the standpipe waste after it joins other waste, but in UPC, and I suspect Canada, 2 inch would be enough.

I don't know if Canada permits horizontal dry vents. UPC does but IPC does not. If you bring the shower drain over to the vertical dry vent, that would not come up.

A bathroom lavatory could provide a wet vent for a shower before the standpipe.

I don't quite understand the question, and I sure don't know anything that needs a a 3.5" slope. What does that mean to you? The maximum minimum slope of anything I know is 2% (1/4 inch per foot).

If somebody knows the Ontario code and could assess your plan, that would be good. Not a lot of regular posts checking layouts on that that I remember.
I don't think so. If you were to join the standpipe drainage downstream of the toilet and if the sink is a bathroom sink (lavatory). and putting the toilet drainage after the lavatory drainage, that may be the only changes you need. At least in US codes, adding the non-bathroom drainage into the mix interrupts the bathroom wet vent rules. I know Canada is more permissive in some points.

Thank you for your reply.

I used the wrong word. Since the distance from the shower to the main is 14', that would be a 3.5" drop using the 1/4 inch per foot slope: which leads me to the 4" pipe since the pipe diameter should be larger than the slope? (which is the question about transitioning from 2" to 4" pipe after the standpipe and shower = maintain the 3.5" drop, but not have the shower and washer standpipe also be 4"...would seem weird to require that)

To make sure I understand, I added a new layout that is numbered:


1) The toilet becomes the primary way waste gets to the existing main, with the lavatory, washer, and shower coming in downstream (instead of the toilet being a “secondary” into the drain that had been coming from the shower)

2) Would the lavatory need to be dry vented here? (I have the space, there will be a 1.5’ cavity in a wall with some ducts)

3) Can bring the shower drain over horizontally towards the standpipe for the washer, vent vertically before the standpipe, then tie the two vents together to have only one that goes across the ceiling?

4) Dry vent on the toilet but before the connection at -1-? (there is the space)

 

[Reach4]

3) Am I properly venting the toilet and sink?

No. See img_3.jpg
Shower and standpipe are ok, but vent separates 6 or more inches above standpipe top.

Red is in different plane than black -- probably higher. Downstream of red vent, the pipe can drop quicker or have a bend.

Lavatory is dry vented, and it wet vents the toilet.

Toilet can optionally go steep before venting, because there is no worry about siphoning; siphoning is needed in a toilet.

 

[DIYCloak]

No. See img_3.jpg
Shower and standpipe are ok, but vent separates 6 or more inches above standpipe top.

Red is in different plane than black -- probably higher. Downstream of red vent, the pipe can drop quicker or have a bend.

Lavatory is dry vented, and it wet vents the toilet.

Toilet can optionally go steep before venting, because there is no worry about siphoning; siphoning is needed in a toilet.

Beautiful. I'll let you know what the inspection says. Should save a couple back-and-forth sessions.