anti fracture membrane

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  #1  
Old 12-22-11, 04:38 PM
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anti fracture membrane

Hello all

I have few questions around anti fracture membrane. I have tile over a concrete slab and we live in California where earthquakes can shake the house. Thus there is a anti fracture membrane between the concrete and the thinset (concrete -> membrane -> thinset -> tile).

I am not clear how this membrane help preventing cracks. After removing some tiles, i noticed the membrane isn't "glued/connected" to the concrete and I can remove the tile by just cutting out the grout. I've been told that's how it is and the tiles just float above the concrete. Because the membrane is not connected to the concrete the concrete can move and crack w/o impacting the membrane therefor the thinset and tile.

Thanks
 
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Old 12-23-11, 06:23 AM
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I live on the other coast, and am not really familiar with earthquake construction. I can however tell you that if the membrane is not bonded to the concrete slab that the tile and grout will indeed fail. Membranes protect against horizontal (side to side) movement, not vertical (up and down) movement. If the membrane is not bonded to the slab, then you will have vertical movement for sure. I know of no membrane that does not require being bonded to a slab.

You have another thread about loose grout and tile. This is why. You mention in the other thread that there are water issues. If there is enough hydrostatic pressure in the slab it could cause the membrame to break bond with the slab. I would find it hard to believe that the membrane was never bonded to the slab.
 
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Old 12-23-11, 09:42 AM
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Thanks Johnny. Without really knowing what the membrane does, I do agree w/ you and your explanation makes more sense than hearing the membrane is not supposed to stick to the concrete.

When I knock on the tiles with a golf ball, some give a hollow sound and most have a more normal sound (not hollow). The few of hollow ones did lift up overtime forcing me to remove and retile that area by cutting grout and what not. After removing the lose tile, the adjacent tiles which didn't sound hollow look properly bonded to the concrete to me. I didn't attempt to cut the grout of those yet but I couldn't slice a thin chisel underneath as I did w/ the lose tiles.

I've been told there are better option now. Instead of using a membrane and thinset, I can use glue which does not crack. But I thought glue (or mastic) would not do well against moisture which is I believe the root cause of the tile being lose.

Thanks
 
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Old 12-23-11, 10:01 AM
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The odds are you're going to have to re-do all of the hollow sounding ones; that's a sign they're no longer adhered as they should be.

Sounds like there may be justification for re-doing the whole floor.
 
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Old 12-23-11, 02:48 PM
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You need to first solve the water issue before you can solve the the tile issue. Its likely that you have some outside grading issues that are causing the water problems inside. After you solve the outside problems the inside problems will go away. Unless you solve the outside water problems you will not be able to solve the tile problems.
 
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Old 12-23-11, 02:57 PM
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Sorry, I'm still not convinced there are water issues, you've only said you suspect there is a water issue; I think you need to figure out whether you really have one. If so, like Johnny said, fixing that comes first.
 
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Old 12-28-11, 03:39 PM
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Would you have any suggestion as how I can determine that or what to look for?

since the problem (tile popping up) was spreading quickly over 6-8 weeks, I must think it's misture and not the concrete slab moving, but I can be sure. Also there is not much bonding between the anti fracture membrane (AFM) and the concrete floor and poor bonding between the thinset and the tiles

At first stepping on the tile sounded hollow but no visible problem for a long time. Recently few tiles start to lift up and the adjacent tiles followed. I had to remove 14 tiles and now ready to put them back.

Pictures showing how much the tile where lifted up



Pictures showing poor bonding



This is right next to a french door thus I went ahead and applied some silicon outside under the door frame. I hope it would reduce the moisture coming into the house.
 
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Old 12-30-11, 06:08 AM
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Its good that you posted pictures, as I can see a few things. For starters, there is no bond at all between the tile and the thinset. The tiles are coming up clean, and the thinset has very heavy ridges. This means that the tile were never pressed into the thinset, and additionally the thinset may have skinned over prior to setting the tile. Additionally, those tiles needed to have thinset burned into the back of them. As to the "membrane", it looks to me like builders felt was used, not an actual tile membrane. Builders felt (tar paper) is not an acceptable membrane and is a guaranteed failure. It also looks like there is no bonding of the "membrane" to the concrete slab at all. If thats what you have, the rest of the floor will failure in a short period of time. It appears that the entire floor is tenting off of the slab, as the membrane was never bonded.

Your floor has failed due to faulty installation methods. Moisture may or may not have something to do with it. That entire floor needs to be demo'd. Test the slab for moisture or have a pro come in and test it. If there are no moisture issues, use an acceptable membrane like Noble CIS or Schulter Ditra on the slab. These membranes are bonded to the slab, as no membrane can "float" under tile and be successful. You should know that membranes only protect against horizontal movement in the slab. If you have vertical movement in the slab, it will likely crack the grout and tile no matter what membrane you select. Could be some special products in your area that may provide better protection. Im from NJ where earthquakes are very rare and much less severe.
 
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Old 12-30-11, 02:44 PM
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Thanks Johnny. In addition to your observations which are very possible, after I removed few tiles that are against the wall I noticed the tiles were installed about 1/4" from the wall which is good. But they filled that gap w/ grout which I wonder why. Then the baseboard was installed over the tile+grout. Aren't we supposed to leave that gap to allow for movement? I think this could why the tile as pushed up because they have no space to move.

Regarding the membrane, it is sticking to the floor for some tiles (hopeful the majority of them). The ones I removed were not sticking, but the adjacent tiles are well bonded. I suspect motion and/or something else is causing the bond to break overtime. I believe this is a liquid applied membrane and I doubt it is as effective as the kerdi ditra.

I would hate to remove and reinstall the baseboards but I might have to do this and remove the grout between the walls and the tiles.

many thanks
 
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Old 12-30-11, 03:35 PM
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Its ok that the tile stops a 1/4" from the walls but that gap should be left ungrouted. Caulk would be ok as that would allow for movement. That area doesnt look that wide though. How long is it? It does look like tenting though. Are there any caulked joints in the length of the hallway or is everything grouted? If you had tenting, a paint on membrane would definitely be the week link and give way first.

The slab looks clean, indicating that whatever was used for a membrane was never bonded or poorly bonded to the slab? Are you sure it isnt tar paper?
 
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Old 12-30-11, 04:31 PM
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It's actually a very large area. The entire first floor is covered w/ this tile. I don't see any caulked join between tile. Is that a soft join to absorb the shifting?

The texture of the black layer feels like chewy putty thus I don't think it's tar paper, but looking at the uniform thickness of it, I no longer so sure it's a liquid applied product.

I purchased some Redgard and I think it probably wont hurt to apply a layer before tiling.

Thanks a lot
 
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Old 12-30-11, 04:44 PM
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Yes, the caulked joint would be a soft joint. If you do not figure out what caused the failure, its not likely that redgard is gonna solve the problem. If you have a large area, make sure that there is open space, no grout, around the perimeter of the rooms. You will also need some soft joints (caulked joints instead of grout) in the field. Good luck, I hope it works for you.
 
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Old 01-01-12, 08:47 PM
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Use Schluter Kerdi as an anti fracture membrane.

It is installed using thinset, not an acrylic adhesive, that moisture effects.
 
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Old 01-02-12, 12:07 PM
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Use Schluter Kerdi as an anti fracture membrane.
Kerdi is a waterproofing fabric membrane and has no "anti fracture" qualities. I think you mean Schluter Ditra.
 
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Old 01-02-12, 12:17 PM
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You could also use Redgard as an anti-fracture across the entire slab. Ditra is nice, but also more costly and takes longer to put on. You can paint redgard in place and it claims to withstand 1/8" movement.

But, wow, those tiles, tenting up like that are some darn interesting pictures. A properly bonded tile should not come up without being destroyed; it should marry tightly to the mortar. Yours look like some I ripped up a year back in a bathroom with many cracked tiles. I think they used a dry mortar and/or cheapest they could find, didn't back burn (technically isn't needed if using proper technique, though I know many do it to be safe anyway).
 
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Old 01-02-12, 12:27 PM
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Redgard and all paint on membranes need to be applied in proper thickness. They typically need 2 coats or more to acchieve proper thickness to provide the antifracture protection they claim to provide.

In my experience, sheet membranes do a better job of isolating the substrate from the tile and provide better protection.

It would appear hear that the op had other issues causing the tile to tent. Grouted perimeter of the room and no soft joints in the field of a large tiled area that did not allow the tile to move and caused tenting. Any isolation membrane, be it sheet or paint on, would fail under these conditions.
 
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