Install Toilet on Concrete With No Closet Flange

What do you do if you remove an old toilet and discover that the closet bolts are rusted out, there is no closet flange, and the waste line is made of terra cotta? You could pay someone $$$$$ to jack hammer out half of your basement floor and connect up to the terra cotta. You could tapcon the toilet bowl to the floor with a rope of plumber's putty like they did in the old days. OR you can do what I did . . .

DISCLAIMER: I am not a licensed plumber. I am not responsible if you injure yourself, cause damage to your property, or violate your local plumbing code.

Step 1: The Problem(s)

Those brown spots above and below the drain pipe are the rusted remains of the closet bolts. I hacksawed the nubs so they were flush with the floor.

The mouth of the terra cotta (or clay) drain pipe is about 7" in diameter. The holes to mount a typical flange line up with the lip of the clay pipe and it wouldn't hold the flange.

Step 2: Break Out the Terra Cotta

The top section of the clay pipe had to go. I chipped it out down to the lower lip (about 1" - 1 3/4" down) using a cold chisel and a hammer.

You can see that I laid ceramic tile in the interim, so I was careful not to chip that.

Also, I covered the lower portion of the drain pipe with duct tape so none of the clay fragments went into the sanitary sewer.

Take your time and chip out a little at a time.

Step 3: Top Part of Drain Pipe Removed

The upper portion of the clay drain pipe is gone. Don't forget to wear safety glasses when forcefully chipping out sharp pieces of clay!

Step 4: Cut ABS Pipe to Length

The lower section is about 4 5/8" in diameter - perfect for accepting a piece of 4" ABS drain pipe. I used the yardstick to mark floor level.

Step 5: Pipe Cut and Fit

The ABS was cut with a mitre saw and dry fit into place. The towel keeps sewer gases from coming into the house.

Step 6: Dry Fit Flange

I dry fit the flange with and without the last ceramic tile.

Step 7: Cement It In

Making sure the ABS was plumb, I cemented it into place with mortar mix.

Step 8: Lay Final Tile

Since I would eventually be drilling into the new cement, I let it cure for a week before laying the final cermic tile with thinset.

Before laying the tile, I used a tile bit to drill holes where the flange would be screwed in. You can see where I cracked the edge of the tile when drilling. :-( No matter. It will be hidden under the toilet bowl!

Again, note the grungy towel stuffed into the hole the keep sewer gases from coming into the house.

Step 9: Install the Flange

I grouted the tile, then . . . the moment of truth:

Using the Tapcon drill bit, I drilled four holes down into the concrete to line up with the holes on the flange. I vacuumed out the holes to get rid of the resulting concrete dust.

I applied ABS cement to the inside of the cemented ABS piece and to the outside of the flange. Then I slid the flange into place and screwed in the Tapcons. I used the kind with the tapered wood screw type head so that once all the way in, they seated nicely in the recessed holes in the flange and held it tight.