# WC flange vs concrete floor



## Mykeeb33 (Mar 6, 2015)

How do you handle floor mounted toilets rough in on a concrete slab pour? I never liked the styrofoam sleeves placed over the stub up because of the difficulty anchoring the flange. CI vs ABS/PVC?


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## Green Country (Mar 6, 2009)

I use the styrofoam sleeves on 3" pvc. I don't like bringing 4" up because the concrete guys have a tendency to hump it up around the pipe. 

I'd be interested in hearing something better too. I don't like jacking with those foam sleeves


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## plumbdrum (Nov 30, 2013)

Sill seal tapes to your desired thickness or armoflex insulation


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## Mykeeb33 (Mar 6, 2015)

What I ended up doing is put nothing on the pipe coming through the floor, or cut it 1/4" under and duct tape the top. On finish, cut pipe off flush with floor, take a metal ABS closet flange, throw away the ABS part, center metal flange over hole, pin it down with Zmac lead anchors. It's illegal, (flange not physically connected to the pipe) but it works great.


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## bct p&h (Jan 19, 2013)

4" pipe with a red cap or dog dish or whatever you want to call it. Come finish, 4" SV flange packed and poured. Doesn't matter if it's cast or plastic. If you know how to do lead and oakum, you'll pull the pipe out of the ground before the flange moves. For a little added security, a few long ¼" lead hit pins into the concrete.


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## plumberN8 (Apr 19, 2015)

4x3 closet 90° are the way to go, pvc is the best waste pipe for the ground around here, we have to isolate the pipe through the slab, most guys use a layer of foam wrap. Just cut it below grade a bit and beat the concrete flush. 4x3 pvc flanges glue right in, drill a few tapcons or hit pins and it's the best damn flange anyone ever tossed a dump through


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## wyrickmech (Mar 16, 2013)

Just buy armaflex 1/2 inch thick. Tape it at the top to keep it from moving during the poor and cut it off and pull now you have just enough room for the hub of either a lead in cast iron flange or a glue flange.


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## KoleckeINC (Oct 22, 2011)

I use foam and instant water stop cement (hydraulic) to hold whatever anchors i have in place. But I hear ya-it's nice to screw a plastic flange down right away versus waiting for the cement to dry.


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## Green Country (Mar 6, 2009)

Even with the styrofoam collars I've never had a problem getting tapcons in. Maybe mine are different than what you guys are talking about?


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## 89plumbum (May 14, 2011)

wyrickmech said:


> Just buy armaflex 1/2 inch thick. Tape it at the top to keep it from moving during the poor and cut it off and pull now you have just enough room for the hub of either a lead in cast iron flange or a glue flange.


I like this way. We still have to protect the rest of the pvc where it touches concrete.

This was new for me when I moved to NC because in Florida we were not allowed to have gaps around any pvc coming though. Roots could and would grow up and around the flange and back into the sewer. 

There was also the potential of the WC resting on the flange and cracking the closet bend below.


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## Michaelcookplum (May 1, 2011)

During a ground work you can always string a line across the footers 4" up(standard) to get the finished floor height and set the flange right then and there. Drop in your screws or drop pin anchors and your done. Any variance of a 1/4-1/2" can be dealt with by any master plumber. I've done it this way a few times but most of the time I use a 4x3 90 and cut off during roughin and drill out to install drop pin anchors


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## rwh (Dec 17, 2014)

We don't have to isolate from slab as far as I know. Nor do we have to seal penetration. Stub up four inch. Cut off flush. Glue in flange. Anchor. Done


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## hroark2112 (Apr 16, 2011)

Some of the inspectors around here don't like the 4x3 flange glued inside the pipe. I'm not sure what their issue is with them.


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## rwh (Dec 17, 2014)

As far as passageway its better than glueing over 3"


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## plumberN8 (Apr 19, 2015)

Most likely because if you use the wrong flange, and there are more than a few, it won't fit in an approved manner, they figure the inspectors are too lazy to get down there and check, and it is something hard to spot if you dont know what to look for. A floor flange should look almost the same every time when it's complete. I've seen 3 " hubs inside 4 " pvc several times, but never seen it hold more than a running test much less an inspection.
https://www.plumbingsupply.com/toiletflanges.html


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## Mr.Layhe (Jul 17, 2015)

Why not preset flange before pour, and duct tape the closet bolt slots top and bottom to prevent concrete from entering.


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## wyrickmech (Mar 16, 2013)

Mr.Layhe said:


> Why not preset flange before pour, and duct tape the closet bolt slots top and bottom to prevent concrete from entering.



Well you can but a lot of times you don't have final floor finish or they change it halfway threw the project. Not saying I'm against it but I have seen on big popes where a lead in flange ended up a inch hi with concert poured up tight to it. Concrete company said we used the wrong bench mark but wouldn't tell us where they came up with there elevation. General sided with the concrete company and we had to chip away.


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## rwh (Dec 17, 2014)

To wyricks point, that is why I find the inside 4" flange the least time consuming. Works every time I have used it. No chiseling around pipe to make room for flange.Plenty of concrete to set anchors in. Easily adaptable to any f.f. elevation. You don't have to cut it until f.f. is determined.


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## Master Mark (Aug 14, 2009)

Mykeeb33 said:


> What I ended up doing is put nothing on the pipe coming through the floor, or cut it 1/4" under and duct tape the top. On finish, cut pipe off flush with floor, take a metal ABS closet flange, throw away the ABS part, center metal flange over hole, pin it down with Zmac lead anchors. It's illegal, (flange not physically connected to the pipe) but it works great.


if you are gonna do that , why dont you just glue down the toilet bowl to the floor with silicone??? That would save you tons of time :laughing::laughing:


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## Mykeeb33 (Mar 6, 2015)

"Why not preset flange before pour, and duct tape the closet bolt slots top and bottom to prevent the concrete from entering?" ................. That's putting way too much faith in the concrete finishers to not mess it up. ...... Can't do that!


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## Mr.Layhe (Jul 17, 2015)

Mykeeb33 said:


> "Why not preset flange before pour, and duct tape the closet bolt slots top and bottom to prevent the concrete from entering?" ................. That's putting way too much faith in the concrete finishers to not mess it up. ...... Can't do that!


It works 85% of the time..all the time.. 😉


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## wyrickmech (Mar 16, 2013)

We always stub up 3 in and slip 1/2 in armaflex insulation on the riser. Simple and fast. It holds the concrete back just enough to slow the hub to slip down to the right height. Also by doing it this way tile and grout will not get in your way either.


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## Master Mark (Aug 14, 2009)

Mykeeb33 said:


> "Why not preset flange before pour, and duct tape the closet bolt slots top and bottom to prevent the concrete from entering?" ................. That's putting way too much faith in the concrete finishers to not mess it up. ...... Can't do that!


that is exactly how we have always done it .... all you got to do is run a plumlb line across the slab and measure the height and normally you will be ok.....


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## plumbdrum (Nov 30, 2013)

The problem with the method of setting flange on rough in is not taking into account what your actual Finnish floor could be. Do you know on the rough what floor type is going over the concrete? The flange should always sit on top of finish floor, and don't give me that throw on a thicker wax crap.


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## wyrickmech (Mar 16, 2013)

I worry about being a 1/8 of an inch hi not low.


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## plumbdrum (Nov 30, 2013)

wyrickmech said:


> I worry about being a 1/8 of an inch hi not low.


 Again all the reason to install after finish floor. I always did the method you suggested, it's just the correct thickness. I also never used all pvc flanges, I spent the extra on the ones with the stainless ring. Plastic flanges always break over time and the steel coated ones almost always rot out.


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## wyrickmech (Mar 16, 2013)

Yes I always use stainless tko stool flanges one it keeps everything out until you set the stool and you never get a call back from a broken flange.


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## GAN (Jul 10, 2012)

rwh said:


> To wyricks point, that is why I find the inside 4" flange the least time consuming. Works every time I have used it. No chiseling around pipe to make room for flange.Plenty of concrete to set anchors in. Easily adaptable to any f.f. elevation. You don't have to cut it until f.f. is determined.


Yep the old adage K.I.S.S. all.

Oatey & Sioux Chief both make what we called a "flush fit" closet flange. Stub up 4"" PVC, wait until floor is finished, cut off pipe flush with finished floor, glue flange inside of 4" PVC, tap con it down and DONE. None of this crap about worrying is the preset flange is at the correct height, or not level, wont rust, no pulling Armaflex from around the pipe and setting a flange (which violates minimum radon protection).

http://www.siouxchief.com/docs/defa...inage/closet-flanges---brochure.pdf?sfvrsn=12


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## rwh (Dec 17, 2014)

Right on GAN!


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## Mykeeb33 (Mar 6, 2015)

plumbdrum said:


> Again all the reason to install after finish floor. I always did the method you suggested, it's just the correct thickness. I also never used all pvc flanges, I spent the extra on the ones with the stainless ring. Plastic flanges always break over time and the steel coated ones almost always rot out.


 :thumbup: Stainless rings sound like the best way to me!


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## FEDguy (May 19, 2010)

hroark2112 said:


> Some of the inspectors around here don't like the 4x3 flange glued inside the pipe. I'm not sure what their issue is with them.


 
According to the NC plumbing code, the inside the pipe flanges cant be used because the inside of the pipe is not approved to be used as a pipe fitting. The NCDOI answered this question on their website.


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## thumper (Aug 19, 2011)

wyrickmech said:


> I worry about being a 1/8 of an inch hi not low.


Heres one that I had to reset, the PVC flange was about an 1"(actually 7/8") above tile floor. This was the men's ADA tolet in a mall. Looks like the rough was too close to back wall, so they used a 2" offset flange. I gave them a price to dig up the floor and do it right.










I knew caulking wouldn't work since I had to get the only ADA toilet back in service, so I used water plug. I always have it and it sets fast.
So it came out decent and they haven't called me back yet. I wrote a disclaimer on my work order since flange was too high. that way if/when it starts to move or leak they won't say "you just fixed it".










Tile floor slopes down to right thats why front gap is bigger. I ran a thin bead of 100 percent clear silicone over waterplug to seal it.


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## 422 plumber (Jul 31, 2008)

My method is to stub up 4" PVC to 1/8-1/4" below concrete. Glue a wafer cap in pipe, then duct tape over it. This way the finishers give you a perfectly flat floor. I then use the 4" spigot flanges, which come in various depths. The concrete guys like it, the floor guys like it, and whoever trims it out likes it. I either use tapcons or lead drive pins to anchor the flange.


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## Michaelcookplum (May 1, 2011)

thumper said:


> Heres one that I had to reset, the PVC flange was about an 1"(actually 7/8") above tile floor. This was the men's ADA tolet in a mall. Looks like the rough was too close to back wall, so they used a 2" offset flange. I gave them a price to dig up the floor and do it right.
> 
> 
> 
> ...



What is a water plug


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## Dpeckplb (Sep 20, 2013)

I usually stub up my 3" abs 3' out of the ground, then slide a 4' piece of 4" PVC around the 3". When it comes time to rough in I drill two holes through the PVC. Stick a piece of iron through it and twist while lifting. The PVC will slide right off, I then cut the 3" flush with the floor and take a grinder to the concrete if there is any high spots. Then I hammer the flange on measure how much needs to be cut off below the floor and use my ridgid inside cutter. Then I glue the inside of the flange and silicone the outside so it will slide down easy. The 4" sewer PVC gives a very close fit on a 4x3 flange.


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## thumper (Aug 19, 2011)

Michaelcookplum said:


> What is a water plug


Its a hydraulic cement, fast setting and is waterproof. I use it to patch pipe penetrations thru CMU walls, temporarily patch cracks in cast iron pipe(especially if there is constant drip or flow), in a pinch on hub joints. Good to have, just have to get used to how fast it sets.
Heres manufactorers info

WATERPLUG®
HYDRAULIC CEMENTFeatures and Benefits:
• Portland-cement-based repair mortar to repair holes or cracks flowing with water.
• Use above or under water or where water is flowing under constant pressure.
• Quick-setting, non-shrinking, permanent.
• Expands as it hardens to lock in place and form a perfect seal.
• Dries in 3 to 5 minutes.
• Compressive strength after 24 hours is 4,000 p.s.i.
• Use interior or exterior; above or below grade;
vertical or overhead on non-moving cracks or joints.
• Completely waterproof, suitable for immersion service.
• NSF approved, suitable for drinking water systems.
• Contains no metallic aggregates, lead or corrosive agents.
• Can be topcoated with appropriate materials.
• Easy to use. One-component powder mixes easily with water.
• Cleans up with soap and water immediately after use


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