Carlos Moreno
New Member
I'm a homeowner doing a full bathroom addition, on a concrete subfloor, in Shoreline, WA. All I have left is tiling, trim, the door, and fixtures. Floor has been leveled with self-leveling compound (SLC)...it is flat and level. My 3" ABS toilet riser pipe currently has a glued-on cap, and I'm visualizing the order of operations for installing the floor tile, cutting off the cap, and installing the ABS toilet flange (gluing/cementing it to the pipe and then screwing it down with tapcons).
Here are my problems: When I poured the concrete, and again with the SLC, I got carried away with leaving space for plumbing...I put too many wraps of foam around the pipe, so I have 3/4" to 1" gap around it. Pipe feels slightly little wobbly in the dirt, but I'm hoping it will be fine once the flange gets screwed to the subfloor. Also, the riser does not come that far into the room...when I eventually cut off the cap the end of the pipe will only be about 3/8" higher than the level of the SLC (which is about 3/4" thick near the riser pipe...actual concrete is under the SLC).
1. What should I do with the gap? I should fill it, right? I'm worried about having enough strong material to screw down the toilet flange into. If I don't fill it, the screws would go in just on the edge of the poured concrete. Should I buy a bag of concrete, mix a tiny bit, and pour it in there? Or would Mortar Mix (the kind I set the tub in...I have some left over) be strong enough? I also have left over Quikrete Water Stop Cement. I would use just a single wrap of foam to leave room to glue the flange.
2. I know the toilet flange should rest on top of the finished floor, so I want to install that last, after the tile. But I don't know yet exactly how thick the floor will be, with thinset, Custom uncoupling mat, thinset, then 8" ceramic tiles (maybe 1/8 + 1/8 + 1/8 + 5/16 ~= 11/16?)...it might end up higher than the cut off riser pipe by 5/16" or so. I'm worried about not having enough room to work with the ABS glue once I have laid the tile...how do I go below the surface of the tile to cut off the cap, and then glue the flange? Would it make sense to go down a few inches and add a 3" coupler so I can bring the riser pipe much higher out of the floor, to make it easier to work with? If not, then what should I do first: Fill gap first? Cut off cap first? Fill gap, lay tile, and then cut off cap?
3. How tightly should I lay the tile around the pipe? I've read that you can either lay it tight and drill holes (with diamond core bit) for screws, or cut notches for screws. Which of those would be best in my situation?
Here are my problems: When I poured the concrete, and again with the SLC, I got carried away with leaving space for plumbing...I put too many wraps of foam around the pipe, so I have 3/4" to 1" gap around it. Pipe feels slightly little wobbly in the dirt, but I'm hoping it will be fine once the flange gets screwed to the subfloor. Also, the riser does not come that far into the room...when I eventually cut off the cap the end of the pipe will only be about 3/8" higher than the level of the SLC (which is about 3/4" thick near the riser pipe...actual concrete is under the SLC).
1. What should I do with the gap? I should fill it, right? I'm worried about having enough strong material to screw down the toilet flange into. If I don't fill it, the screws would go in just on the edge of the poured concrete. Should I buy a bag of concrete, mix a tiny bit, and pour it in there? Or would Mortar Mix (the kind I set the tub in...I have some left over) be strong enough? I also have left over Quikrete Water Stop Cement. I would use just a single wrap of foam to leave room to glue the flange.
2. I know the toilet flange should rest on top of the finished floor, so I want to install that last, after the tile. But I don't know yet exactly how thick the floor will be, with thinset, Custom uncoupling mat, thinset, then 8" ceramic tiles (maybe 1/8 + 1/8 + 1/8 + 5/16 ~= 11/16?)...it might end up higher than the cut off riser pipe by 5/16" or so. I'm worried about not having enough room to work with the ABS glue once I have laid the tile...how do I go below the surface of the tile to cut off the cap, and then glue the flange? Would it make sense to go down a few inches and add a 3" coupler so I can bring the riser pipe much higher out of the floor, to make it easier to work with? If not, then what should I do first: Fill gap first? Cut off cap first? Fill gap, lay tile, and then cut off cap?
3. How tightly should I lay the tile around the pipe? I've read that you can either lay it tight and drill holes (with diamond core bit) for screws, or cut notches for screws. Which of those would be best in my situation?
