[williamj001]

I was wondering if it is possible to lay tile (18"x18" Travertine) directly over 5/8" Plywood that is fastened to a concrete subfloor? If so, is there a water sealing/proofing i should put on the plywood before hand or a specific thinset I should use?

 

[PaliBob]

I don't think any tile guys would tile over the plywood. They would just tear off the plywood and tile over the concrete.

 

[Just Bill]

I agree. Plywood and mortar moisture don't mix well. Tear it up as suggested or add a 1/4 layer of backer board, hardibacker or duroc.

 

[mike costello]

Why would you lay backer board over concrete?

 

[AllanJ]

Why would you lay backer board over concrete?

If you chose not to tear out the plywood first.

(say, if the floor height was more problematical with the plywood removed.)

In addition, the plywood subfloor, if there was give, would result in the tiles' disintegrating.

 

[ARI001]

Remove the plywood if you can. If not lay down 1/4" fiber cement board in a bed of thinset mortar screwed to the plywood. If you where to install tile on any other floor this is how it would be done. I usually add admix to the thinset in all phases of the installation. This is a little costly but I have never had a call beck for cracked tiles. You do not need to seal the plywood but you do need to prime the floor (concrete also) with an adhiesive primer before installing the fiber cement board. It is not neccesary to do this on top of the fiber cement for the tile.

 

[rusty baker]

This is a project destined to fail. Plywood will not last put over concrete. No type of wood sheathing is a good idea over concrete.

 

[heedah]

have you seen tavy thin skin?

Laying tile over plywood sounds like an accident waiting to happen. I just used Tavy thin-skin - 1/32" membrane glued to the sheet vinyl over plywood. It is lighter than cementboard and won't add height to the floor. Word of note - the instructions are poor. In addition to the ones they give you with the product I suggest the following: Wear long dish gloves - the glue is like flypaper and does not unstick from you easily; spread a very very very thin layer of glue with your flat trowel first then notch it-that's the only way to prevent excess mess and make the glue last long enough for the roll of membrane; don't step on the membrane once it's down-the glue comes thru on your shoes (which makes me wonder how Tavy can suggest immediately floating the floor with thinset...I'm waiting a day); work quickly once the membrane is down-the glue is very tacky and will not allow you to reposition the membrane easily. I ordered online for pickup at Lowes.

 

[Bud Cline]

That is one of the worst products on the market and can not possibly do what the maker says it will do. It is a physical and scientific impossibility.

You are trusting your expensive tile installation to a tub of contact adhesive.

 

[JazMan]

Plywood or OSB over concrete.........Bad Idea.
Tiles, especially stone tile over plywood..........Bad Idea.
Installing a tile backer over concrete......Bad Idea.
Installing backer over ply over concrete.....OH man.....That is really bad.

Will only those who are tile experts answer tile questions please. If you're not an expert you can go ahead with your 2 cents, but please mention your level of knowledge.

Jaz

 

[williamj001]

Why is plywood over concrete a bad idea? I'm sure I have seen professional contractors do it that way, I could be wrong. Is there something that should go inbetween the plywood and concrete? How elsewould you go about laying nail down flooring to a concrete subfloor?

 

[rusty baker]

I've seen "professionals" do many things that shouldn't be done. Plywood or OSB on concrete will fail.

 

[ARI001]

Plywood installed over concrete is usually done so over treated sleepers or sleepers installed over top of felt (required by code). As long as this is the case in this situation installation of backer board is not an issue. Plywood or OSB fastened directly to concrete will be destroyed by rot caused by moisture from the concrete which is why it is a bad idea to install plywood directly to concrete. Jazzman- 16 years in the construction industry and three years in cabinet making industry, and yes I am actually a licensed general contractor Class A BLD =)

 

[williamj001]

Cool, thanks for all the great info. The ply wood is definately coming up now but I do have a couple more questions in regards to what my options are. If I went with the "sleepers" option are these like wood sleepers 1" by 4" treated wood? And If I go with tile I now have a 3/4" gap left by the plywood I take out, any good suggestions on how to fill that 3/4"?

 

[ARI001]

The sleeper may be 1x4 but more typically would be 2x4 which when removed would leave you with 1 3/8" (1x4)to 2 1/8" (2x4) gap respectively. You can drill a hole in the plywood and stick a rod through the hole to verify the depth. There is no economical way to raise the floor this much that I know of. Your best bet is just to replace the trim to hide the difference. However if the plywood is attached to sleepers there is no reason to remove it. If the plywood is directly on the concrete I would remove it if you can (it may be installed in a bed of mastic, if so you will have to grind the slab with a floor grinder, also the sleepers maybe installed in a bed of mastic as well) and install the tile directly on the slab. You should then only have approximately 3/8" gap which is easily covered with shoe or quarter round. You will still have to replace the casing mouldings around any doors this is unavoidable.

 

[Homeowner1111]

For those who have asked if tile can be set over plywood, the answer is YES, with amazing results. I have done it twice, using Tavy products and the results are perfect. Follow the directions, and if you have questions, the owner of Tavy will speak to you directly to help. This only raises the tile about 1/8" but saves hours of labor tearing out the old plywood. Highly recommend!

 

[JazMan]

For those who have asked if tile can be set over plywood, the answer is YES, with amazing results. I have done it twice, using Tavy products and the results are perfect.

You're misunderstanding the subject. If you're installing the tiles over The Tavy membrane, you are not installing them over plywood.

The only plywood some people would have to remove regardless of how/what method, is any ¼" underlayment which is often luan used under vinyl.

Tile direct over plywood is never preferred although it can be done over a double layer system using specific products and methods.

Jaz

 

[ryansdiydad]

For those who have asked if tile can be set over plywood, the answer is YES, with amazing results. I have done it twice, using Tavy products and the results are perfect. Follow the directions, and if you have questions, the owner of Tavy will speak to you directly to help. This only raises the tile about 1/8" but saves hours of labor tearing out the old plywood. Highly recommend!

When someone's first and only post is a glowing product endorsement, especially when it's not in response to any question, it just seems bogus to me.

 

[stick\shift]

Agreed. Anyone can join and post but credibility only comes with time. Having worked on forums with JazMan for more than a decade now, I know anyone who disagrees with him is probably wrong.

 

[JazMan]

Having worked on forums with JazMan for more than a decade now, I know anyone who disagrees with him is probably wrong.

You haven't met my wife. :smile::biggrin2::vs_laugh::vs_blush::wallbash:

Jaz