Closet flange install in basement floor

I need to istall a closet flange for a basement toilet. There is cermic tile already istalled around the PVC pipe in the floor.

My question is - If the flange is glued in and sitting flush on top of the tile, is that all I need to do to secure the flange? Should I also use masonary screws to screw the flange to the concrete floor?

Thanks, Jack

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The PVC pipe is 4 inch and I have a inside fit closet flange. The pipe is cut level with the tile, but when I try to dry fit the flange, it does not sit flat on the floor (maybe 1/8 inch above). I used a little bit of vaseline (which I will clean off completely before gluing) to make sure the flange was inserted as far as it could go.


Should I try to cut the PVC so it is recessed slightly below the level of the ceramic tile to allow me to get the flange to sit flat on the tile?

Thanks, Jack

A PVC joint is an interference fit...i.e., the socket of the device is smaller than the piece you are trying to fit into it. (In the case of an inside fit, the flange is tapered, and gets tighter like a plug as it goes in.) When you add the cleaner and the cement, the outer surface of the pipe and fitting melt, and fuse together. In other words, it is often nearly impossible to dry fit pvc pipe and fittings...you must measure. If you did get them to bottom out, you might have a huge problem getting the apart to then glue it up. If the flange does not have a champher that would prevent it from bottoming out when you add the cement, it will go all the way down. If there is a champher, then you will likely need to cut the pipe back a bit. Look at the bottom of the flange - is the junction square or not? Also note that because of this champher, you must hold things in place until the solvent diffuses, or the fitting can ooze itself back off because of the taper and the lubrication from the cement. Maybe put a box of tile on it or something until it sets up. It's a good idea to use the screws on the flange to hold it in place. Keep in mind that it probably isn't the greatest idea to have the plastic the only thing holding the toilet in place...anchor the flange, especially if it is all plastic. You may need a diamond bit to make a hole through the tile. Some floor tile is really hard. A good tile-setter will often notch the tile so he doesn't have to drill through them later to set the flange anchors in.

The flange does not have to totally bottom out, so measure carefully then make the cut and allow a little space, no more than 1/8". When I anchor anything into concrete, I use lead sleeves and #12 screws. For a flange, I would use stainless steel screws. The sleeves need a 5/16" hole and I drill these with a rotary hammer drill. I find this easier than tapcons, but they would also work.

Thank you

Thank you for your responses, Jack

I got to thinking about this. I don't really understand why the flange would need to be screwed down. The flange is glued to 4 inch PVC which is encased in the concrete floor. I don't think it's going to move. I guess I am not looking forward to trying to drill 4 holes through cermic tile and concrete (without a hammer drill).

Is this a subject that is a matter of opinion, or is it a clear cut requirement to screw down a PVC flange into a concrete floor? Just looking for other opinions.

Thanks, Jack

jfhardy said:

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I got to thinking about this. I don't really understand why the flange would need to be screwed down. The flange is glued to 4 inch PVC which is encased in the concrete floor. I don't think it's going to move. I guess I am not looking forward to trying to drill 4 holes through cermic tile and concrete (without a hammer drill).

Is this a subject that is a matter of opinion, or is it a clear cut requirement to screw down a PVC flange into a concrete floor? Just looking for other opinions.

Thanks, Jack

Click to expand...

Screw it down. This helps to support the flange. If the flange is all plastic in time it will break where the bolts enter the slots. We use flanges with stainless steel rings but also screw them down. It's the proper thing to do.

John

The bolts that hold the toilet fit into the slots...you tighten the toilet down, you torque the flange...screw it down or you'll warp the flange.

Thank you for the responses. I screwed it down with tapcons. Drilling through the cermic tile was not easy.