Prepping concrete for tile

jlcharles · 11-04-2007, 12:32 AM

I have a concrete slab foundation that I would like to install ceramic tile on. There is a lot of black residue from the old asbestos tiles. (I didn't remove them) I had the residue tested and it is not asbestos.

I tried scraping it off with a heavy 6" scraper, which you'll see in the photos of the area. It isn't coming off unless I bang on it with the edge of the blade. Is there an easier way of doing this? Something I can apply to make it come off a bit easier? Without making it impossible for the thinset to stick?

And a close up so you can better see what I'm dealing with.

And in case you want a bit of background on what is going on, we had a flood early in the year. The previous owner put in a bathroom upstairs and tapped a 2 1/2" PVC drain into a 1 3/4" galvanized steel pipe. Needless to say, I clogged the kitchen sink, past where the pipes all meet and we had the contents of upstairs bathroom floating in our kitchen. It's taken a while, but as you can see, we had the plumbing fixed. (Ended up getting a new water main put in too, since ours was corroded. No wonder the tap water was awful) Anyway, we get to put in a new kitchen. Before I head into the living room.

tyler101 · 11-04-2007, 10:47 AM

The product you are dealing with is called cutback. Here is a link to some options for removing it. http://johnbridge.com/vbulletin/showthread.php?t=12850

jlcharles · 11-06-2007, 01:23 AM

Cool, thanks. Good stuff in that thread. I think I'll go for the Flexbond after making sure the loose stuff is off the floor.

jlcharles · 11-07-2007, 01:01 AM

Another question in relation to this. The floor is very smooth, so I bought an angle grinder with a masonry wheel (I'm sure I'll need more than one) to rough it up. As I was reading the instructions, it mentioned wire brushes and how they can be used to clean concrete. Is it possible to remove the cutback using a wire brush on an angle grinder?

I will have my shopvac running while I hit the floor with the grinder to keep the dust levels down. And as I said before, no asbestos in the cutback.

tyler101 · 11-07-2007, 01:35 PM

The only bad thing will be is that you are going to stir up quite a bit of dust. The Diamond Cups they talk about on that forum are different than a wire wheel. The cups they are talking about are like this http://www.masterwholesale.com/shop/...ding-Cups.html .

jlcharles · 11-07-2007, 01:49 PM

This is similar to what I purchased:

http://www.lowes.com/lowes/lkn?actio...524&lpage=none

It wasn't dewalt, but I think it was a Norton brand item.

I have no problem with the dust, I'll seal off the kitchen area and keep the shopvac running close to the grinder to catch most of it.

11-04-2007, 12:32 AM	#1
jlcharles Newbie Join Date: Sep 2007 Posts: 4	Prepping concrete for tile I have a concrete slab foundation that I would like to install ceramic tile on. There is a lot of black residue from the old asbestos tiles. (I didn't remove them) I had the residue tested and it is not asbestos. I tried scraping it off with a heavy 6" scraper, which you'll see in the photos of the area. It isn't coming off unless I bang on it with the edge of the blade. Is there an easier way of doing this? Something I can apply to make it come off a bit easier? Without making it impossible for the thinset to stick? And a close up so you can better see what I'm dealing with. And in case you want a bit of background on what is going on, we had a flood early in the year. The previous owner put in a bathroom upstairs and tapped a 2 1/2" PVC drain into a 1 3/4" galvanized steel pipe. Needless to say, I clogged the kitchen sink, past where the pipes all meet and we had the contents of upstairs bathroom floating in our kitchen. It's taken a while, but as you can see, we had the plumbing fixed. (Ended up getting a new water main put in too, since ours was corroded. No wonder the tap water was awful) Anyway, we get to put in a new kitchen. Before I head into the living room.

11-04-2007, 10:47 AM	#2
tyler101 Firefighter/Paramedic Join Date: Oct 2007 Location: Ohio Posts: 27	Prepping concrete for tile The product you are dealing with is called cutback. Here is a link to some options for removing it. http://johnbridge.com/vbulletin/showthread.php?t=12850

11-06-2007, 01:23 AM	#3
jlcharles Newbie Join Date: Sep 2007 Posts: 4	Prepping concrete for tile Cool, thanks. Good stuff in that thread. I think I'll go for the Flexbond after making sure the loose stuff is off the floor.

11-07-2007, 01:01 AM	#4
jlcharles Newbie Join Date: Sep 2007 Posts: 4	Prepping concrete for tile Another question in relation to this. The floor is very smooth, so I bought an angle grinder with a masonry wheel (I'm sure I'll need more than one) to rough it up. As I was reading the instructions, it mentioned wire brushes and how they can be used to clean concrete. Is it possible to remove the cutback using a wire brush on an angle grinder? I will have my shopvac running while I hit the floor with the grinder to keep the dust levels down. And as I said before, no asbestos in the cutback.

11-07-2007, 01:35 PM	#5
tyler101 Firefighter/Paramedic Join Date: Oct 2007 Location: Ohio Posts: 27	Prepping concrete for tile The only bad thing will be is that you are going to stir up quite a bit of dust. The Diamond Cups they talk about on that forum are different than a wire wheel. The cups they are talking about are like this http://www.masterwholesale.com/shop/...ding-Cups.html .

Prepping concrete for tile