Replace toilet flange w/ old thinner (schedule 30?) PVC?

[MOV]

Hi all,

We had rotted subfloor in our bathroom that has since been torn out and I'm ready to lay down the new plywood. The problem is getting the plywood under the lip (outer ring) of the toilet flange. Ideally I'd like to just saw it off and glue a new flange in after the floor is installed... however, our 1972 house was built with some kind of older PVC that is thinner and does not connect to today's thicker white schedule 40 PVC. Please see the attached images.

Is this schedule 30? Or old CPVC? Or something else? It was installed with orange primer.

If so, how can I connect a new toilet flange to a schedule 30 or CPVC drain pipe? Tearing out all the old plumbing and vent pipes is not an option, so I either need a way to connect to this older pipe or get the plywood subfloor and underlayment under the ring of the flange.

Thanks!

 

[MOV]

The way I see it, these are my 2 options. Obviously it would be preferable to install a new flange and keep the subfloor as one piece... but I'm stumped as to how to connect a new flange to the pipe so I'll have to do option B if I can't.

 

[Sponsor]

 

[Reach4]

You want to identify a pipe. Measure the OD.

To do that, measure the circumference. You can do that by wrapping something around, make a mark. Unwrap. Measure. Divide by pi.

 

[MOV]

Ok, here's what I've got. It reads:

3" FEDERAL MOGUL THIN WALL DWV ASTMD 2949 PVC TYPE 1

Inside diameter is 3".
Outside diameter is 3.28"
Pipe walls are 0.14" thick.

 

[Terry]

If the OD is the same, I would cut back downstream of the 90, use a coupling and put a new elbow in with new flange.

 

[MOV]

I've found recommendations for these two different types of adapters:

https://www.supplyhouse.com/Fernco-3009-33-3-x-3-ProFlex-Coupling-Thinwall-PVC-to-Sched-40-PVC

• Would you trust that connection right under a toilet? (We have a new Kohler Cimarron going in).

https://www.amazon.com/Genova-Products-65330-Schedule-Adapter/dp/B000BQW9FM

• I assume I could just use plain old purple primer and PVC cement on that one? (i.e. not CPVC cement, but the regular stuff to connect this thin wall DWV to modern schedule 40)?

Where would I be safe making a permanent, leak-free connection with either coupling?

 

[MOV]

Thanks Terry, you mean like this?

 

[Reach4]

https://www.supplyhouse.com/Fernco-3009-33-3-x-3-ProFlex-Coupling-Thinwall-PVC-to-Sched-40-PVC

That is 3.45in by 3.19in . That may be close enough. Regular 3 inch PVC is 3.50 inches OD.

I don't think they should have been using that thin stuff there, but I could be wrong.

 

[Terry]

Thanks Terry, you mean like this?

Yes, like that.

 

[hj]

You probably need an SDR x sch 40 bushing.

 

[MOV]

Pardon my ignorance... based on the information about the old pipe:

3" FEDERAL MOGUL THIN WALL DWV ASTMD 2949 PVC TYPE 1

Inside diameter is 3".
Outside diameter is 3.28"
Pipe walls are 0.14" thick.​

... is anyone able to officially identify and confirm the type of pipe this is?

I've seen the terms "thinwall PVC" and "Schedule 30" and "SDR 35" and various adapters/couplers/bushings that use these terms as well. I just want to be 100% sure I'm buying the right size coupler and using the right PVC cement.

Thanks guys!

 

[Reach4]

I just want to be 100% sure I'm buying the right size coupler and using the right PVC cement.

Cement with purple primer and regular PVC cement.

IAW HJ's post,
https://www.homedepot.com/p/NDS-4-in-x-4-in-PVC-DWV-x-Sewer-and-Drain-Adapter-3P16/100377417

 

[MOV]

Cement with purple primer and regular PVC cement.

IAW HJ's post,
https://www.homedepot.com/p/NDS-4-in-x-4-in-PVC-DWV-x-Sewer-and-Drain-Adapter-3P16/100377417

Thanks, though I would need a 3" version, such as this one.

https://www.amazon.com/Genova-Products-65330-Schedule-Adapter/dp/B000BQW9FM

The description says "3 inch adapter bushing adapts 3 inch schedule 30 to 3 inch schedule 40" so I just wanted to be 100% sure this thin wall stuff I have is indeed schedule 30 (and not, say, CPVC). I've seen Oatey's CPVC cement and it is orange... and since my old pipes are dripping with orange that was throwing me for a loop.

 

[Reach4]

The description says

The description says ABS.

You should not mix ABS and PVC.

https://www.ferguson.com/product/ge...spigot-plastic-dwv-bushing-g65330/_/R-2389712 says PVC. It is not so clear on the size. https://www.genovaproducts.com/schedule30pvcdwv.html has more size info, but you will need to look up the meaning of those terms.

But even so, http://www.charlottepipe.com/pl_pvc_sch30_thin_wall.aspx says schedule 30 would be 3.25 OD.

D2729 pipe is 3.25 OD.

3.25 is very close to your 3.28 OD measurement. Maybe you had the caliper cocked a tad.