Basement Bathroom Advice

[Zerocool749]

Hi everyone,

I'm planning to build a bathroom in my basement and wanted feedback on my plan.

• Layout - I am adding a three piece bathroom to the corner of my basement. I went with this basic layout and this 30" x 60" shower pan. The shower fixtures will be accessible from a closet on the other side of the wall. The backwater valve will be located and accessible from a closet on the other side of the wall. I am having a professional plumbing install the rough plumbing for the three drains. I will install the AAV vent, hot and cold supply, etc.
• Walls - I plan to frame my walls 1" away from the foundation walls. So, to measure the drain locations, I measured 1" from foundation, then 3.5" for 2x4 wall. Then, I could measure drain locations from the walls.
• Flooring - The shower pan will go directly on the concrete with a mortar bed. It's level and flat already. The rest of the bathroom will get Dricore subfloor and LVP flooring
• Venting - This bathroom is located +15' from the main vent stack to extends to the roof and under the basement concrete floor to the city sewer outside. So, I plan to install an AAV in the wall with an access panel. It would be located basically under the window, 4' higher than sink p trap.

Here are the images to help,

https://imgur.com/a/i3mHyQv

Here are the questions I have:

• Am I right to put the shower pan directly onto the concrete instead of on top of the Dricore subfloor? That's what I read is best. Use a mortar bed for the shower pan to concrete. Then rest of bathroom will be on Dricore subfloor.
• Do the specific locations of the shower drain, toilet drain, and sink drain make sense?
  • I gave the toilet 30" width and located the drain 15" from shower and 12" from wall.
  • I gave the sink 36" width and located the drain centered to that area and within the wall.
  • I located the shower drain 15" and 12" from wall cavity. That's based on the shower pan manufacturer.
• Will an AAV work for venting this bathroom? How exactly would I install that? Connected to the sink drain?
• Anything else I didn't consider?

Thanks for any help you can provide!

 

[Reach4]

Just checking... the sewage goes to a city sewer and the big pipe exits thru the basement floor, right?

 

[Sponsor]

 

[Zerocool749]

Yes, you got it! The main stack exits through the basement floor and goes to a city sewer in front of my house. The green tape in my pictures shows where the main sewage is under my basement floor. I had a plumber camera it and locate it to help with this planning.

 

[Reach4]

I did not loosen my browser settings to try to see your photos. Actually I loosened one thing, and then gave up. I will comment that sometimes it is easier to join sewer lines out in the yard than under the concrete. Your sewer lines will be down a ways, so cutting or breaking the concrete may be best for you.

 

[Zerocool749]

Here are the photos to help!

This shows the location of where the bathroom will go. The green tape represents where the main line is. It exits the house to the left in this image. The blue tape outlines the rough walls I plan to build for the bathroom.

This shows the dimensions and how I calculated where the shower, toilet, and sink drain will go. I'm going to give these dimensions to the plumber .

This is a cleaner image to show the drain locations that I plan to give to the plumber. It measures from the foundation walls.

This shows where the main stack is located in relation to where I plan on putting the bathroom. It's a cast iron stack. The green tapes show the line for where that main stack goes under the basement floor and out to the city sewer in front of my help.

 

[Reach4]

All fittings wye, 45, combo, and long sweeps. Green is 3 inch.

 

[Zerocool749]

Thanks for that diagram! I'm having a professional install that rough plumbing. I'll compare what they do to your diagram.

For venting, would I use a sanitary tee to add a AAV on the lavatory line? I would use a access panel so I could get to the AAV.

Also, for the flooring, can I put the shower pan directly on the concrete and the rest of the bathroom on a Dricore subfloor and LVP finished flooring?

Thanks for your help so far Reach4!

 

[Reach4]

For venting, would I use a sanitary tee to add a AAV on the lavatory line? I would use a access panel so I could get to the AAV.

Yes. 2 inch out of the santee.

The AAV bottom needs to be at least 4 inches higher than the trap arm, but up higher, as you are planning, is perfectly good.

 

[Zerocool749]

Great, I can put the AAV up higher in the wall and have the access panel hidden behind a mirror above the sink. Looks like I have a good plan.

 

[Jadziedzic]

"I plan to frame my walls 1" away from the foundation walls. So, to measure the drain locations, I measured 1" from foundation, then 3.5" for 2x4 wall."

You'll want to add 1/2" to the "from the foundation walls" measurement if you're planning to cover the framed walls with drywall...

 

[Zerocool749]

Hi Jadziedic, thanks for taking a look at my situation!

1. According to the installation guide, the shower pan goes directly against the studs, so I don't think I need to account for drywall when measuring the shower drain location.
2. The sink drain goes within the wall cavity like this, correct? So, I don't think I need to account for drywall when measuring the sink drain location.
3. For the toilet, is it 12" from the studs or from the finished wall with drywall? If it's from the finished wall, then yes, I need to add a 1/2", you're right! Thank you

 

[wwhitney]

3) Yes, the 12" "rough" dimension is from center of closet flange to finish wall surface behind the tank. If there's a baseboard running behind the bowl, the clearance for that also needs confirming.

Cheers, Wayne

 

[Zerocool749]

Thanks Wayne! I didn't think about baseboard either. Now my measurement from center of toilet flange to finished wall surface is 17 1/2".

1" air gap from foundation wall + 3 1/2" stud + 1/2" drywall + 1/2" baseboard + 12" distance = 17 1/2"

 

[wwhitney]

Thanks Wayne! I didn't think about baseboard either. Now my measurement from center of toilet flange to finished wall surface is 17 1/2".

1" air gap from foundation wall + 3 1/2" stud + 1/2" drywall + 1/2" baseboard + 12" distance = 17 1/2"

Typically the tank hangs farther back than the base, so you wouldn't count the baseboard. But the spec sheet for the toilet should indicate the free space at the floor level, and if it indicates 3/4", then you would have to pull the toilet farther out if using, say, a 1" thick baseboard. [But not by 1", maybe just 1/2".]

Cheers, Wayne