Ugh. Raised box around wastepipe on slab. Best way to remedy before tileing?

[Gator95]

Ok, just pulled up all the old tile and the 1" thick mortar bed below it. Down to slab now, and the slab is lookin' good. No cracks at all. Then I found this around the ABS waste pipe. (haven't gotten to taking off old flange yet)







It's a raised area about 1/2" high (irregular height) around the waste pipe, square in shape.

I'll be laying tile in on the slab... but do I need to do something about this 'box' to get it level to the floor?

Do I just roughly chip it out so it's no more than 1/8" above slab and then count on the thinset to smooth the irregularity once I lay the tile? (Tiles will be 12" squares.)

Or is it necessary to completely level it down, prime, and put down some self-leveling mortar?

Any suggestions appreciated. Also explanations about why this would be there.

[Uncle Cracker]

I think I'd go ahead chip out below the surface a little and go with the mortar patch, because staying above and counting on the thin-set may leave voids that could trap water, possibly contributing to mildew or loose tiles in the future. Always best to do tiling on a fairly smooth surface, and you'll always get a flatter tile surface that way. And this particular location is gonna get wet more than most. Just my preference, however.

[pelligrini]

How is your new tile finish floor elevation going to work with the hall or room finish floor? Tile & mortar thickness, etc. It had a thick mortar bed before, was it much higher than the other floor? If it wasn't, you might want to float your bathroom floor instead.

[Gator95]

How is your new tile finish floor elevation going to work with the hall or room finish floor? Tile & mortar thickness, etc. It had a thick mortar bed before, was it much higher than the other floor? If it wasn't, you might want to float your bathroom floor instead.

Yep, the bathroom floor was about 5/8" above the hall floor. It will actually probably look better now. The only artifact I can think of is that the gap between the bathroom door and the floor will be pretty big, but I can mitigate that some with the threshold.

This is a downstairs half-bath, about 6x7', the entire floor was about 1"-1.5" built up from the slab. Will have to cut down waste pipe and add new flange... which was subject of another thread

[poolhound]

I think I'd go ahead chip out below the surface a little and go with the mortar patch, because staying above and counting on the thin-set may leave voids that could trap water, possibly contributing to mildew or loose tiles in the future. Always best to do tiling on a fairly smooth surface, and you'll always get a flatter tile surface that way. And this particular location is gonna get wet more than most. Just my preference, however.

I agree with Unc. You are always better to go slightly below the surface and then level and then counting on the thinset than intentionaly leaving raised areas. Having laid around 2,000 sq ft of 20" tile through my house a couple of years back I can attest that you dont want any slight bumps.

While you always want your tile as flat and evenas possible this is especially important around the toilet bowl as it can easily end up rocking - not good!

I dont want to throw in another wrench but I wonder what you will find when you take out that old flange and wether the depth of the exposed soil pipe will be at the level you want and how a new flange will fit...

[Gator95]

I dont want to throw in another wrench but I wonder what you will find when you take out that old flange and wether the depth of the exposed soil pipe will be at the level you want and how a new flange will fit...

My plan was to tile around the waste pipe first, then use a sawsall to cut the pipe down to the level of the tile, then glue a inside-fit flange to the waste pipe, then screw the whole thing down to the slab. I'm figuring there should be plenty of pipe above the floor given I took out a 1 to 1.5" mud bed, and the floor will wind up being about 3/4" lower or so.

Am I thinking about this right? Or is here something fundamental I'm missing?

[crokett]

Just to ensure there is enough pipe I would cut the toilet flange away from the pipe and leave as much of the pipe in place as you can. You can cut the flange away in sections and use a flat screwdriver to pry the pieces off, carefully. I've done it on two toilets where I didn't have a choice but to do it that way.

[poolhound]

My plan was to tile around the waste pipe first, then use a sawsall to cut the pipe down to the level of the tile, then glue a inside-fit flange to the waste pipe, then screw the whole thing down to the slab. I'm figuring there should be plenty of pipe above the floor given I took out a 1 to 1.5" mud bed, and the floor will wind up being about 3/4" lower or so.

Am I thinking about this right? Or is here something fundamental I'm missing?

sounds like a plan