Toilet rocks when dry-fit to new flange

[Dormer_man]

This is a new installation of a toilet to a concrete floor in the basement.

The plastic soil pipe was sawed off flush with the concrete floor.

The plastic flange was glued to the exterior of the soilpipe, and the flange sits flat on the floor.

The flange was TAPCON philips-head screwed into the concrete.

When I dry tested fitting the toilet to the floor, it rocks from front to back.

I think the horn of the porcelain toilet base may not be sitting flat on the top of the soil pipe.

Will the wax seal with plastic cone take care of this problem?

Do I need to use plumber's putty around the perimeter of the base?

Should I shim the base of the toilet, or should I take a grinder and try to remove some of the soil pipe without damaging the flange?

If I shim should I use plastic shims or metal washers?

How would I secure the shims so they don't move in the future?

What should I use to fill the gaps between the shims?

Sorry for all the questions, I am just trying to do this right the first time, I hate sewer gas.

[Tom R]

First, - - I think I would check the bottom of the toilet base for any obvious imperfection (like a run from the mold), - - that could be carefully grinded off.

If there's nothing 'obvious', - - then I would 'shim' the toilet with plastic shims, - - either the front or the back (and then each side), - - according to which way will make it sit more level, - - then after it's all in place run a bead of silicone caulk around the front and both sides, - - but not the back, - - this way you'll be covered for appearance, - - but yet the opening in the back will leave you an 'alert-clause' if the wax seal ever fails.

Usually your flange should not sit higher than 1/4" above your finished floor. A lot of flanges are thicker than 1/4".

But I have had similar problems with toilets from the Big Box stores. They're not called cheap for nothin'.

[Tom R]

Oh, - - and as far as 'securing' the shims, - - put a dab of caulk on them before sliding them into place, - - and slide them in an extra 1/16" so you can get a nice caulk line on your front and sides with no interference.

One week after the toilet is installed, - - go back and very lightly re-tighten your toilet bolts, - - sometimes it will still be 'settling-in' on the wax seal after the initial 'install'.

[roger g]

If the flange bolts come through the base of the toilet then you can assume that it is sitting in the right place. The wax seal is very forgiving to cover any discrepancies. I usually stand on the toilet to make sure the wax is compressed enough and that is usually enough to stop any rocking. By the way..... what are you doing to make it rock.
Anyways if you need to shim it anything that doesn't rust is good. Brass.plastic, etc etc. then silicone around the perimeter of the toilet and let it set. The shim aren't going to move especially if they are attached to the silicone.
"They" recommend putting plumber putty underneath first but it is a lousey job so I've only ever tried that once.


roger

[rabadger]

Are you going to lay a tile floor? If so see how it fits with the tile down.

[Dormer_man]

Thank you Tom, Roger, and Richard for your interest. As usual, your comments are right on the money and have really helped.

Just to prove to myself the soil pipe was not too high, I took a wood chisel and knocked off about a quarter inch of plastic all around. The bowl still rocks.

Tom,
I bought a Kohler Wellworth bowl for $49. There was a cheap knock-off bowl available for $17 but I opted for the Kohler instead. I checked the horn for imperfections, but it looked fine. You were right about the flange thickness (are you psychic or what?) The flange is 3/8 inch thick, not 1/4. I think the extra thickness is causing the rocking issue. I put a bubble level on the bowl and it was leaning back about a quarter inch too low. Three plastic shims on the back make it level. The side to side level is off a tad, but not enough to shim. Thanks for the tip about re-tightening after a week.

Roger,
When I dry-tested, I set the bowl on the flange with no wax seal installed. And I did not install the bolts either. Then I rocked the toilet from side to side and front to back. There was no movement side to side, but front to back there was a quarter inch of play. When I install the wax seal, I will sit on the bowl with my gal in my lap. I weigh 190 and she weighs 130. Plus she will hold our pit bull who weights 55 pounds. We're talking 375 pounds of pressure, which should squish the wax pretty good.

Richard,
Thanks for the thought about the tile floor, but to expedite getting the toilet up and running, we have opted to just sit the bowl on the concrete for the time being. The floor is painted with Benjamin Moore high gloss battleship gray paint. But you are correct, if we installed tile, it just might raise the bowl enough to not ride on the flange like it is apparently doing now.

[Dormer_man]

Tom, Roger, and RABadger,

Thanks for the help. The toilet is up and running with no leaks. Tom, the shims at the back made it level. Roger, you were right about the wax seal being very forgiving. After I tightened the bolts, the bowl sits rock solid. I will wait a week or so to let it settle and tighten the bolts a little more.

[giddonah]

I'm glad this came up, I'll probably be doing this very thing as I just tiled a bathroom and the flange is 1/4" or so above the tile and now I know what to do if it rocks. I like reading solutions to other people's problems before I have them myself.

[rabadger]

Don't tighten the bolts to much. You will crack the bowl.