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apollo1 · Oct 18, 2006, 07:45 AM

I am adding a toilet, shower and lav to the basement. Concrete is cut out and trenches dug. The bath group will be vented. My question is I am studding out block walls and the shower will be located in the corner.(block wall studed out on left and block wall studded out on back of shower) Right side I will build a partition.

Question 1:When I plumb in the 2" trap for the shower (fiberglass 2 piece. Base/walls) and stub it up I plan on setting the base over the hole to get it as close to perfect as I can for the shower drain.(I won't be able to move to the left or back) Will I have any play with the shower drain? Or does this stub up have to be dead nuts?

Question 2: Which shower drain should I use?

Question 3:I plan on sinking a 6' inch pipe around the 2" shower stub up before I concrete for drain clearance. How far should the 6" pipe go down into the concrete. In other words how deep will the 6" void be around the 2" shower stub up? I know the drain doesn't take up much room but by going deeper will that give me some play in the stub up for drain installation. What is the standard void depth?

Anyone have an answer for me?

speedball1 · Oct 18, 2006, 08:17 AM

"Question 1:When I plumb in the 2" trap for the shower (fiberglass 2 piece. Base/walls) and stub it up I plan on setting the base over the hole to get it as close to perfect as I can for the shower drain.(I won't be able to move to the left or back) Will I have any play with the shower drain? Or does this stub up have to be dead nuts?"
I dunno about, "dead nuts" (sounds kinky to me) but the shower drain MUST line up with the trap raiser. What I would do is set the shower base where you want it to be and mark the center of the drain on the slab. I would then take a measure off two walls, (three is better) and install the trap and stub-up dead on.

"Question 2: Which shower drain should I use?"
One should have come with the base but unless they're a replacement drain they're all pretty much the same. (see image)

"Question 3:I plan on sinking a 6' inch pipe around the 2" shower stub up before I concrete for drain clearance. How far should the 6" pipe go down into the concrete. In other words how deep will the 6" void be around the 2" shower stub up? I know the drain doesn't take up much room but by going deeper will that give me some play in the stub up for drain installation. What is the standard void depth?"
The only time we dap out for a trap raiser is for a bathtub installation. For showers we allow the cement men to pour over the trap leaving just the stub-up to connect the shower drain to. Think about it. You can only sink the 6" pipe as low as the trap sets. Even then you have fittings glued in that are immovable. Now a exception to this is if you were running cast iron with lead and oakum joints. Then you would have a little "wiggle room" to move the trap and raiser but my advice is to get it right the first time.
Good luck, Tom

apollo1 · Oct 18, 2006, 10:27 AM

Tom, Thanks for the quick response. I will take measurements to get stub up "dead on. But,Below is a clip from the shower installation instructions. Notice "C". It says 6" diameter hole but it does not say how deep though!

Pre Installation Requirements
a. In remodeling, if necessary, add studs at each end to provide a vertical nailing surface for the side nailing flanges of bath fixture product.
b. To avoid obstruction during installation make sure that supply lines, spout pipe and valve plumbing do not project into alcove.
c. Shower stalls require a 6" (150mm) diameter floor opening for 2" (50mm) IPS drain fitting connection. [See Diagram 1]

Thanks again

iamgrowler · Oct 18, 2006, 10:56 AM

The 6" opening is meant to accommodate the bottom portion of the drain body, which protrudes a good 3-1/2 to 4 inches from the bottom of the stall when the drain body is installed.

The shower drain Tom recommended is a glue type, which is meant more for applications where you have access to the underside of the shower base.

When setting a shower base on concrete, a 'No-Caulk' drain body is a lot easier to install.

I would suggest the '140 Series' from Oatey.

speedball1 · Oct 18, 2006, 04:07 PM

Plese excuse the bad advice about the shower drain. In all of our new construction we rough for tile showers. Most of the manufactured shower bases that I've seen set up from the floor, need to be bedded and don't recess the drain. But things have changed since I retired I guess. Sorry. Tom