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Unread 01-18-2022, 09:23 PM   #181
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Join Date: Aug 2014
Location: FL
Posts: 506
Thx CX for speedy response and for bearing with me. FYI, gmail now seems to send email notifications from this forum to spam . Hopefully it's only for me.

Originally Posted by CX
As usual, I'm confused. It appears that you've already installed a first layer of subflooring with the plywood oriented in the correct direction. This is not the actual subfloor?
That is correct. It is not the actual subfloor. There are 3 structures in this bathroom:

Structure 1: The actual subfloor (which you have identified as such). The new sub-floor I have installed is at the same plane/level as the rest of the bathroom floor.

Structure 2: A raised platform from 2 x 6 for the bathtub area. This platform will have 2 layers of 3/4" BC ply on it. In lack of better terms I referred to this 2 ply layers as sub-floor. I can now see why this is confusing. How would you call it then? I guess I'll just call it the Tub's platform 2 ply layers/flooring.

Structure 3: I didn't want to just continue the tub's platform all the way to the wall and then build the shower at the same level as the tub. It makes for a really dangerous drop in height in a wet area (height of curb + height of platform). This is how the previous shower was built and it was really unsafe. Instead, I am planning to embed the shower within the 2 x 6 Platform. But, the shower drain pipe is in the way. Since there is no crawl space underneath, all plumbing are above the sub-floor and hence the need for a platform. Structure 3 is raising the floor level (above the actual subfloor) to the top of the shower drain pipe. Otherwise, I will need to create a mud bed 5 inches thick (4" to the top of the PVC pipe + 1" the required thickness of the pre-slope at the drain).

Originally Posted by CX
Why have you left out the subfloor across the entire length of the drain line?
So as per the above, this is not the real subfloor. It is an extra structure on top of the real subfloor. Ideally I would have used 2 x 4s instead of 2 x 3s and have the pipe fully below the floor of the structure. I can't do it or else the preslope and slope wouldn't fit within the height of the 2 x 6s. I don't want to build the tub's platform from 2 x 8s or 2 x 10s or else there will be an even bigger step down from the platform. Here is the math (a plan is attached as well):

Embedded shower build up:
Height to top of shower drain pipe: 4"
Height of pre-slope at the drain: 1"
Height of pre-slope at the opposite end of the shower: 4' x 0.25 pitch = 1"
Height of slope: 1.5"
Total: 4 + 1 +1 + 1.5 = 7.5"

Surrounding area (Tub's platform build up):
2 x 6 joists: 5.5"
2 ply floors: 1.5"
CBU: 0.5"
Total: 7.5" exactly what I need for the shower without making the platform higher than necessary...

I have marked the floor of the 3rd structure with "A" and "A" prime in the plan.

Hopefully the pics above make more sense now...
Attached Images
Attached Images
File Type: pdf Curbless v6.drawio.pdf (54.8 KB, 35 views)
Much like this project, my posts are still under construction
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