# Ditra Membrane over existing Vinyl floor



## R&D Tile (Feb 6, 2006)

Remove the vinyl and any 1/4" underlayment that might be there as well if this is over a wood subfloor, then inspect the subfloor and see what's there.


----------



## Bud Cline (Mar 12, 2006)

The problem with tile over vinyl is not usually the vinyl itself. We keep saying that and saying that and saying that. I would think Schluter would have wised up by now.

I agree with R&D: REMOVE THE VINYL and its related underlayment.


----------



## JazMan (Feb 17, 2007)

I agree with what the other experts have told you to do.

In addition, under the heading of "Limitations", item 2, it says "cushioned vinyl unacceptable". Did you miss that part? page 9.

From your description of the tears and sealing the patch, I believe your sheet vinyl is cushioned. It doesn't feel like carpet, but cushioned non the less. If _I'm right_ your floor has a printed pattern on a very thin layer of foam with a clear wear layer over it, making it cushioned. Most if not all sheet vinyl wider than 6' is cushioned. Inlaid floors were no wider than 6'.

Is your floor on a slab or is it a suspended wooden subfloor? 

Jaz


----------



## fjlcisco21 (Aug 9, 2009)

It's a suspended wooden subfloor. I did not miss the part about the cushioned vinyl. Again, it surprised me to see that they would allow installation of the membrane on top of vinyl. I'm following all of your advise on this, I will be removing the vinyl floor. Now, what is the reason for removing the wood underneath it? That part I'm lost on. Can you elaborate? I would figure that after I took up the vinyl and prep the plywood, I would be ready for the membrane.


----------



## Bud Cline (Mar 12, 2006)

> Now, what is the reason for removing the wood underneath it?


One reason is no one knows how that wood is installed. There could easily be voids under that layer that would go unnoticed with a vinyl floor but would be disastrous with a rigid tile installation. Too much potential for movement.

Another reason is because those plywoods used for vinyl underlayments aren't the best products around. Everyone cheaps-out on underlayments and the availability of quality solid plywood underlayments is limited. The layers sometimes contain voids where knots were removed and those voids are then ignored in assembling the plys. Too much potential for movement.

Another reason for removing the vinyl is the method of perimeter-gluing the vinyl when it is installed. Not everyone has the ability to recognize a vinyl floor that has been only perimeter glued. It is easier in the long haul to remove the vinyl.

Another reason is the cushion vinyl already mentioned. Not everyone has the ability to identify cushion vinyl.

Another reason is the desire of most people to "get by as cheap as they can" and this means they may use the cheapest thinset they can find. The cheap thinsets have a place in the industry but using them to attach ceramic tile to a vinyl product isn't one of their places.

On the Internet we like to be as safe as humanly possible when prescribing methods of installation. Installing ceramic tile over vinyl is one area that always draws controversy.

Vinyl over concrete is a different issue and we also recommend that vinyl also be removed but not necessarily for all the same reasons.


----------



## fjlcisco21 (Aug 9, 2009)

Great post Bud, Thanks for the explanation. I'm just trying to learn the correct way to do this. I've laid tile before, but not on suspended wood subflooring, always on concrete slab....Couple of more question if I may, sorry in advance for the ignorance :huh: and it should probably be and easy answer, but here it goes:

1) The 1/4" plywood is also under the kitchen's cabinets, do I just remove the plywood around the cabinets and leave the rest under there? What's the best way to remove the plywood?

2)Once I pull the 1/4 inch plywood used as underlayment for the vinyl, what do I need to replace it with? I'm assuming if the subfloor is okay beneath that and it's thick enough (5/8?? perhaps) should I then proceed? Sorry to ask so much, but on this part I'm not very versed. Thanks again for everyone's time.....


----------



## Bud Cline (Mar 12, 2006)

> 1) The 1/4" plywood is also under the kitchen's cabinets, do I just remove the plywood around the cabinets and leave the rest under there? What's the best way to remove the plywood?


The neat and tidy method is to use a "toe-kick saw" but that's a specialty tool that you don't find everywhere. Probably the next best tool would be a "sonic saw", Rockwell offers a great sonic saw for about $129, Dremmel also has one.

The next best thing and cheapest way to do it is a hammer and chisel.

One other method is to use a utility knife to repeatedly cut the ply at the base of the cabinets until you can break the ply away from the cabinet. That particular type of plywood is generally soft and not too difficult to cut with a utility knife.

Cut around the cabinets and forget about it.




> 2)Once I pull the 1/4 inch plywood used as underlayment for the vinyl, what do I need to replace it with?


Well you can use any number of cement board products, or Schluter DITRA would work nicely.


----------



## fjlcisco21 (Aug 9, 2009)

Bud Cline said:


> Well you can use any number of cement board products, or Schluter DITRA would work nicely.


Removing the 1/4" plywood does not sound that bad then.....I was thinking I needed to add more plywood here (another sheet of 5/8" plywood) before installing the ditra membrane. I'm not going with natural stone, I'm using porcelain tile so no need to have 1 1/4 inch worth of plywood?


----------



## JazMan (Feb 17, 2007)

OK, so, how thick is your subfloor now? If it's only 5/8" ply, I recommend adding an underlayment of min. 3/8" ply. 1/2" would be much better, the more the better 5/8" is great. :thumbsup: A 3/4" ply subfloor should be fine for porcelain + Ditra or any CBU, but again the more the better. 

Jaz


----------



## Bud Cline (Mar 12, 2006)

ABSOLUTELY "more is better" but the 1/4" is never good anywhere in the mix. That's why it needs to be removed, then adding back an additional (minimum of 3/8") layer of plywood is a good idea. It may sound strange to remove the plywood only to put more plywood back in but the 1/4" ply can be a serious issue.


----------



## fjlcisco21 (Aug 9, 2009)

Bud Cline said:


> ABSOLUTELY "more is better" but the 1/4" is never good anywhere in the mix. That's why it needs to be removed, then adding back an additional (minimum of 3/8") layer of plywood is a good idea. It may sound strange to remove the plywood only to put more plywood back in but the 1/4" ply can be a serious issue.


Got IT!! Thank you both Jazman and Bud for your guidance on this. I feel a lot better now that I know exactly waht is to be done. I'll keep posting the progress of the floors and any issues that I may encounter along the way. :thumbup:


----------

