Toilet Flange install question for 3" pipe

[LarryM13]

Ready to install my toilet flange in my basement bath (tiled over concrete)

I have a 3" PVC pipe sticking out of the ground and am installing a 4" PVC toilet flange over the 3"

I've been reading around a bit, besides wishing I went with a 4" PVC coming out of the ground so I can slide a 3" inside, I seem to be noticing differing opinions on: primer and glue or just glue for flange connections.

I can see a 3" flange going inside a 4" pipe as maybe not needing the primer as waste/water won't be exposed to the seam between the 3" flange and 4" pipe, but what about the 4" flange going over the 3" pipe?

I would assume in my situation, primer and glue to weld that seam to not let any waste/water get through is the appropriate method?

Praying this flange doesn't break, primer/glue would be a nightmare to repair.

Thanks!
Larry

 

[Reach4]

Gluing the flange into place is normal. Here are a couple flanges that do not get glued:
888-GPM is shown in http://www.siouxchief.com/products/drainage/residential/closet-flanges/pushtite as having a plastic ring, but I think it is actually a stainless ring. You would definitely prefer to have metal rather than plastic for the ring.
https://terrylove.com/forums/index.php?posts/449676/ has a photo in a store with dimensions added.

A compression flange goes on the outside of the pipe.
https://www.plumbingsupply.com/toiletflanges.html#torqueset It seems to say it can go over 3 inch PVC. The compression happens when you tighten the 4 bolts. The screws that mount this to the floor are not shown. If you get this flange, post a couple of pictures. You would have to shape the floor around the PVC to clear the tightening screw mechanism and still leave wood for the mountings screws to screw into

There may be others of both styles.

 

[Sponsor]

 

[LarryM13]

Gluing the flange into place is normal. Here are a couple flanges that do not get glued:
888-GPM is shown in http://www.siouxchief.com/products/drainage/residential/closet-flanges/pushtite as having a plastic ring, but I think it is actually a stainless ring. You would definitely prefer to have metal rather than plastic for the ring.
https://terrylove.com/forums/index.php?posts/449676/ has a photo in a store with dimensions added.

A compression flange goes on the outside of the pipe.
https://www.plumbingsupply.com/toiletflanges.html#torqueset It seems to say it can go over 3 inch PVC. The compression happens when you tighten the 4 bolts. The screws that mount this to the floor are not shown. If you get this flange, post a couple of pictures. You would have to shape the floor around the PVC to clear the tightening screw mechanism and still leave wood for the mountings screws to screw into

There may be others of both styles.

Thanks for the info, unfortunately I have to stick with the flange unit I have as I have had to trim the base to make it fit since my sweep sat high (due to builder not digging deep enough)

 

[Reach4]

Thanks for the info, unfortunately I have to stick with the flange unit I have as I have had to trim the base to make it fit since my sweep sat high (due to builder not digging deep enough)

Then prime and glue. Get the pipe height right, because there is no second chance.

I initially did not understand "my sweep sat high". I now think you mean that that the pipe does not stay straight deep enough to let that Push-tite tail go down. If you did feel like doing something else, chipping concrete is likely not as big of a deal as you might think. Still, the prime and glue is the norm. I do think it is one of those things that you may do better the second time than the first time.

 

[Jadnashua]

Priming with PVC does two things...cleans the area to be cemented, and pre-softens the surface so that the cement can work properly before the solvents evaporate. You're solvent welding the pieces together...literally melting the plastic on both pieces, and when the solvent evaporates, they literally become one. Without the primer, the bond strength is not as strong. Might not leak, but definitely not as strong. Because the socket on most of those fittings is tapered, and the diameter is large, you might want to place a weight on the top to hold it down for awhile...otherwise, it might just slowly push itself up, then harden, creating a major pain. The taper is why you can't dry fit the pieces together...without softening the plastic, they don't fit! It's sort of like driving a wedge into the thing, and with the cement in there, it becomes slippery, and doesn't stay unless held until things become stable. Normally, it will be stable after about 30-seconds, but not if you have a bit excess cement. Just as easy to weigh it down, and then not worry about it.

 

[Terry]

Sioux Chief makes a closet flange that glues inside a 3" pipe.
Cut the pipe off flush with the floor, and it will glue inside. You can secure the outer ring to the floor with tapcons.