Flooring Tile - Removal of mud/thick-set for new ceramic
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spelunker2
02-20-06, 12:42 AM
Like a previous posting from Austin TX, we removed the slate tile in our entryway to replace with more modern ceramic tile. It hought this would be a relatively simple DIY project to spruce up a 1982 home.
Instead we found much to our dismay that there is a ~2" + thick layer of loose sandy mortar like substance underneath the tile and on top of a very roughly finished concrete slab. This entryway is level with a formal living room, and 6-7" above a 'sunken' living room/den. Pulling the carpet corner in the formal living reveals a well finished and smooth slab at about 1/4" below the level of the top of the old 1/4" thick slate tile in the entryway. The sunken living/den also has a smooth finished slab. Only the entryway is this mess of mortar/mud/whatever. This stuff is so loose that a wet/dry vac sucks/digs holes in it in lots of places. I've 'dug' a couple of holes to determine the thickness to the real concrete and it appears pretty consistent, but again the finish of the concrete below is extremely rough/bumpy.
Around the edges of the room it looks like a latexish mastic, or maybe leveling compound was used in place of thin set mortar to set the slate tiles, but the rest of the room looks like the slate was simply set into the mud/thick-set mortar directly. Pulling some of those tiles brings up large uneven chunks of 'mud' with the tiles (up to 2" thick"). Many of them though came up relatively cleanly leaving a smooth(ish) surface.
The previous poster was concerned with putting in a wood floor, and so wanted quick cure times so he wouldn't have to wait 3 years to install wood. I want ceramic tile, so I have slightly different questions.
1. Should I go ahead and remove all of the 'mud' or leave what is there in place and use more to build back up to level? What material should be used here (think inexpensive - it's about 130 SQ Ft.) ?
1.5 Is there a minimum thickness that thick-set/mud should be applied? Do I need to dig down to ensure that I get at least that thickness?
2. How long must this be allowed to cure before laying tile (using thin set to actually lay the tile I assume)?
3. If using mud to buildup/level, how do I handle the now jagged and uneven step down to the den? Do I use a form as you would for pouring concrete slab?
4. Because I can't change the floor level due to the front door, and a stairway, I have to have the new tile at the same level. The new tile is 3/8" thick compared to the 1/4" thickness of the old slate. I also have to account for 1/16" - 1/8" of thin set - which apparently wasn't the case on the slate. So it seems I'll be too tall if I bring back to the current level. Is there a better way to do this than what I'm talking about?
5. Our kitchen is on the same level as the entryway and also steps down into the den. It has a ceramic tile though. I had been intending to replace it, but not if it's this much trouble. Is it likely to be the same situation?
6. Why on earth would a builder do it this way? Why not just level the slab and use thin-set for the tile? This doesn't seem to have been any less work - so what's the rationale?
-Disheartened :confused:
Instead we found much to our dismay that there is a ~2" + thick layer of loose sandy mortar like substance underneath the tile and on top of a very roughly finished concrete slab. This entryway is level with a formal living room, and 6-7" above a 'sunken' living room/den. Pulling the carpet corner in the formal living reveals a well finished and smooth slab at about 1/4" below the level of the top of the old 1/4" thick slate tile in the entryway. The sunken living/den also has a smooth finished slab. Only the entryway is this mess of mortar/mud/whatever. This stuff is so loose that a wet/dry vac sucks/digs holes in it in lots of places. I've 'dug' a couple of holes to determine the thickness to the real concrete and it appears pretty consistent, but again the finish of the concrete below is extremely rough/bumpy.
Around the edges of the room it looks like a latexish mastic, or maybe leveling compound was used in place of thin set mortar to set the slate tiles, but the rest of the room looks like the slate was simply set into the mud/thick-set mortar directly. Pulling some of those tiles brings up large uneven chunks of 'mud' with the tiles (up to 2" thick"). Many of them though came up relatively cleanly leaving a smooth(ish) surface.
The previous poster was concerned with putting in a wood floor, and so wanted quick cure times so he wouldn't have to wait 3 years to install wood. I want ceramic tile, so I have slightly different questions.
1. Should I go ahead and remove all of the 'mud' or leave what is there in place and use more to build back up to level? What material should be used here (think inexpensive - it's about 130 SQ Ft.) ?
1.5 Is there a minimum thickness that thick-set/mud should be applied? Do I need to dig down to ensure that I get at least that thickness?
2. How long must this be allowed to cure before laying tile (using thin set to actually lay the tile I assume)?
3. If using mud to buildup/level, how do I handle the now jagged and uneven step down to the den? Do I use a form as you would for pouring concrete slab?
4. Because I can't change the floor level due to the front door, and a stairway, I have to have the new tile at the same level. The new tile is 3/8" thick compared to the 1/4" thickness of the old slate. I also have to account for 1/16" - 1/8" of thin set - which apparently wasn't the case on the slate. So it seems I'll be too tall if I bring back to the current level. Is there a better way to do this than what I'm talking about?
5. Our kitchen is on the same level as the entryway and also steps down into the den. It has a ceramic tile though. I had been intending to replace it, but not if it's this much trouble. Is it likely to be the same situation?
6. Why on earth would a builder do it this way? Why not just level the slab and use thin-set for the tile? This doesn't seem to have been any less work - so what's the rationale?
-Disheartened :confused:
Tilebri
02-20-06, 06:50 AM
Given how crumbly it is, I'd pull it all out. Rent a chipping hammer and it will come apert very quickly. Self leveling cements are out of the question based on costs and regular cement has a 28 day wait to cure for setting the tile so I'd just go ahead and re mud it. Get sand mix and bagged sand, mix the sand mix 4 shovels to 1 shovel full of sand. This will give you the 4-1 sand/portland mix you want. Mix with water until it's like sand castle sand so it's not to wet and very packable. Set screed guides in the recess so the tops are level with where you want the finished height. Spread some thinset onto the slab and start packing the mud down. Pull a straight edge along the scredd guides to get the mud to the level of the guides. Troel over the packed area to get some portland to the top of the mix, slide the screed guides and fill the slots with more mud while the area is still wet. Set tile the next day.