Tub/shower to Shower conversion - before I dig

[Russell Harris]

Hello, a few questions and some advice on this tub/shower to shower conversion. I'm installing a Woodbridge (Home Depot) pan with a linear drain. I'll have only one shower head and it will be low flow. The pan is a 36" wide so the drain is offset (roughly red circle in photo) a bit from existing drain as it was a 1985 standard tub. So a few questions regarding the drain retrofit and what I do and don't need to dig out/change.

- I'm ok with the idea of 1 1/2" drain for the shower. I'm not worried about a washrag blocking the drain or having shower spa over flow. I'm in an ETJ and no inspection in TX, just follow common sense and modern code. 1.75 gpm shower head.

- However, I don't have an issue with digging out the drain and fixing/modifying it, BUT only what's need for the pan drain to connect properly.

- It seems like there is asphalt around the tub drain stub up. Was that common? See bottom of old tub drain.

- What is the part/method I need to go from the shower pan drain outlet to the existing drain. I'll have some offset left to right and a slight bit away from front/control wall.

- The pan is spec'd to be set in mortar. After I get the drain configured, do I need to add in some concrete fill around the drain to fill the old tub drain space.

The forums have gotten me through my remodel so far, I appreciate your advice!

Thanks!
RH in Austin

 

[John Gayewski]

Show us your bottom. It looks like a no caulk drain could be used below that linear drain but without seeing the hole who could know? Unless someone here has done that model or knows what it looks like from below.

 

[Sponsor]

 

[Jadnashua]

How deep is the p-trap?

The shower pan is probably not rated for the hole to be that large, so yes, you may need to fill in some of that. You'd want to drill some horizontal holes in the existing slab and stick some rebar stubs in there to help anchor the patch, and probably grind off the asphalt so you had clean concrete for the patch to bond to. What do the instructions say about a hole around the drain?

One thing the mortar under the pan can do is to help ensure it ends up level. The second thing is to support it so it feels more robust, and doesn't flex which can cause stress fractures over time. Not supporting it around the drain can make that worse.

 

[Terry]

You will want to dig out the drain, and relocate a p-trap for that.
Mortar set the pan, yes.
You don't need to fill in around the trap though.

 

[Russell Harris]

Thanks everyone for the questions and advice. I'm laughing at that 'show us your bottom' request

Here's more info and a question regarding Terry's reply. First pics of the pan bottom. I did look at the installation instructions and it mentions having at least a 6" diameter hole around the drain location. So while bigger than they mention, probably within spec. It's an acrylic pan, and seems very rigid.

I've included a pic of some digging I did and regarding Terry's mention of digging up and replacing the whole P trap assembly. Could I try and cut the threaded hub piece out of the 1 1/2" fitting and then using a socket saver, ream out the fitting. Then I would use a street long sweep 90 out of the reamed fitting, get over the 2-3" diagonally to where the shower drain center is and long sweep 90 up again into the shower. Would that be suitable if the measurements work?

 

[Jadnashua]

Dig out a bit more.

You don't really want a couple of 90-degree bends in the path otherwise, if you ever got a clog, you'd never get a snake down there. Plus, it looks like that's a 45 degree angle...depending on what it's connected to, you might be able to cut the piece behind that angle and get your drain exactly where you want it without all of those angles. Won't know until you dig a big more out. Also, anything above the trap, especially with angles, can accumulate crud, and over time, that can start to smell...really hard to clean it out with those angles, too.

 

[Russell Harris]

Dig out a bit more.

You don't really want a couple of 90-degree bends in the path otherwise, if you ever got a clog, you'd never get a snake down there. Plus, it looks like that's a 45 degree angle...depending on what it's connected to, you might be able to cut the piece behind that angle and get your drain exactly where you want it without all of those angles. Won't know until you dig a big more out. Also, anything above the trap, especially with angles, can accumulate crud, and over time, that can start to smell...really hard to clean it out with those angles, too.

Ok, I'm back! Took a while to get to the digging. Plus, this asphalt/roofing tar has been a bear to get through. Anyway, I've exposed what I guess is the top of the P trap and also the main line which is really close to the left of the P trap. They used lots of wye fittings in this install ( I dug up both toilet areas trying to move a toilet). The main line is right on this line so I guess it was just a tight fit for this tub's P trap. So, can I do a hub saver ream out of the top of the P-trap? In looking at the top of that P trap fitting, I'm sorry I forget the name but is that a reducing hub going from 2" to the 1 1/2" fittings?

Thanks as always!
RH