Tile over plywood

[PeterT]

I realize this is a garage forum, but I've gotten some good advice on this website so I want to try this question. It may have been asked before, but my search didn't show up an answer to my exact question.

I bought a new home and the lower floor, about 400 sqft is linoleum. I want to tare up the linoleum and put down tile. I really don't want to spend the money on cement or hardie board but will if it has the benefits. The biggest downsize to cement board is the added height (on top of the already added tile height).

I've tiled before but over concrete. I know they make an orange foam that can be put down but that stuff is really expensive.

So my question is, can I use a mortar thinset directly over the plywood, then put the tile down? Would I get cracks from the floor shifting? Any economical options for me?

Thanks in advance,

 

[Swexan]

It can be done but a lot depends on what your situation looks like. How big is the span between your floor joists, what size are the floor joists, etc. What causes the cracks is when the floor flexes underneath the thin set. that includes the floor joists flexing from the added weight. If the floor joists are big enough and not too far apart you can get away with it. But I would add at a minimum another layer of plywood to get the thickness to at least 1 1/4 inch thick to minimize movement. You should also screw down the plywood, no nails.

My advice is based on experience only, I am by no means an expert so many others will probably chime in and tell me that I am wrong

 

[shoot summ]

Deflection is the issue, tile and grout are very intolerant of movement under them.

You need to find out how thick the floor/subfloor is, how far apart and what size the joist are, and how the floor/sub was fastened to the joists.

Go hang out on the tile forums at johnbridge.com, they have lots of good info there.

 

[Jack Olsen]

The short answer is no. Plywood is generally not stable enough for tile. There are options -- like CBU or Ditra. But there's no free lunch on this issue.

 

[txusa03]

The short answer is no. Plywood is generally not stable enough for tile. There are options -- like CBU or Ditra. But there's no free lunch on this issue.

I would agreed. Plus anything wood is going to expand/contract and cannot be used as a solid surface for tiling. Don't take the shortcut with this one.

 

[nmk_61802]

What are the adjacent flooring surfaces? Are the floors level between? Common practice is to install a 1/4" subfloor under a sheet floor. You could tear that out and replace with Ditra or 1/4" Hardiboard and keep the floors fairly level.

 

[ml504]

We put down 1/4" hardiboard over the plywood and then tiled on top of that. Never had a crack or problem in the 6 years before we moved. It was tempting to put it directly down over wood but everyone we spoke to talked us out of it.

 

[southalabama]

yep, just make sure the floor doesn't flex.

http://www.dannylipford.com/installing-tile-over-a-wood-subfloor/

 

[rwhite692]

Can you do it? Yes.

Is it the best process? No.

Backerboard (Hardieboard or similar), installed as per the manufacturers instructions, joints taped and mudded, etc, is the most dimensionally stable base material (aside from tiling on a concrete slab)

The second-best method: Put down 1/2" MDF and tile directly over that.

Using that method, I did around 2,000 square feet, 18" square tiles, 1/8" grout spacing, and it has been down for 10 years now, with NO problems.

I put the MDF down with construction adhesive and using a bostich pneumatic stapler that drives 1 and 1/4" "horseshoe" staples and sets them just sub-flush. Take time to align the sheets so that the joints between sheets are extremely tight, almost invisible.

If you don't want to put down the MDF, and you want to tile direct over the plywood subfloor (again, I'm assuming it is 1 and 1/8 ply), you will need to spend a real good amount of time inspecting all of your joints where the sheets meet, checking for deflection, adding additional nails/screws where necessary to tighten things up. Level any sheet-to-sheet height variances with a belt sander and/or use a product like dash-patch, to level things out where necessary.

But...If you put the tile down direct over the subfloor....don't be surprised if you wind up with some grout cracking, eventually.

 

[rwhite692]

yep, just make sure the floor doesn't flex.

http://www.dannylipford.com/installing-tile-over-a-wood-subfloor/

The process described at the link you posted, includes the use of backerboard over the subfloor, and also a discussion about tiling over old/existing tile....

Not tiling directly on the plywood subfloor, which is what the OP asked about....

 

[shoot summ]

Can you do it? Yes.

Is it the best process? No.

Backerboard (Hardieboard or similar), installed as per the manufacturers instructions, joints taped and mudded, etc, is the most dimensionally stable base material (aside from tiling on a concrete slab)

The second-best method: Put down 1/2" MDF and tile directly over that.

Using that method, I did around 2,000 square feet, 18" square tiles, 1/8" grout spacing, and it has been down for 10 years now, with NO problems.

I put the MDF down with construction adhesive and using a bostich pneumatic stapler that drives 1 and 1/4" "horseshoe" staples and sets them just sub-flush. Take time to align the sheets so that the joints between sheets are extremely tight, almost invisible.

If you don't want to put down the MDF, and you want to tile direct over the plywood subfloor (again, I'm assuming it is 1 and 1/8 ply), you will need to spend a real good amount of time inspecting all of your joints where the sheets meet, checking for deflection, adding additional nails/screws where necessary to tighten things up. Level any sheet-to-sheet height variances with a belt sander and/or use a product like dash-patch, to level things out where necessary.

But...If you put the tile down direct over the subfloor....don't be surprised if you wind up with some grout cracking, eventually.

I wouldn't recommend MDF or particle board if you are any where near a source of moisture.

 

[rwhite692]

I wouldn't recommend MDF or particle board if you are any where near a source of moisture.

Agree - This is in the common area of the home, not in a kitchen or bathroom, etc.

 

[PeterT]

Ok, thank you all for your replies,, I price out the work using hardie board or cement board.

 

[Beaumont67]

I put down exterior 3/4" plywood for a tile floor and 3/8" plywood down for a hardwood T&G floor.
- all plywood is PL400 glued with deck adhesive (1/2 jumbo tube per sheet)
- all plywood is wood screwed down (every 4-6 inches)
This method really tightens up the floor...no cracked grout...and dissimilar floors are level flush with each other.

 

[theoldwizard1]

My son rebuilt his bathroom from the floor joists to the rafters. New 3/4" plywood.

His tile guy glued and screwed 1/4" backer to the plywood before starting to tile.

 

[bobemmerich]

If the linoleum is sound and flat, there is a thin set mortar you can use to go over it. I wouldn't recommend it though. I would use the 1/4" backer board or 1/4" cement board, with the tile and mortar, it would probably add about 1/2" or so.

 

[kippieland]

The short answer is no. Plywood is generally not stable enough for tile. There are options -- like CBU or Ditra. But there's no free lunch on this issue.

We used Ditra on our kitchen floor. Went right over the existing lino. with no problem. Great stuff but have to make sure you use the right morters in the directions or pealing can occur. Little pricey but worth it for reducing floor height increase.

 

[larry4406]

As many have stated, deflection is the issue/concern. For the builder I worked with, large kitchen areas/foyers had 1/2 inch durrock applied over the 3/4 OSB sub floor which was on TJI floor joists 16" o/c, not sure of span of joist size. When marble was used, we decreased floor joists to 12" o/c and used 3/4" plywood overlay vs the durrock (i think it was hem/fir plywood).

In new construction, all of these plies are taken in to account and cabinets, stairs, etc, are elevated to work off net floor height.

In a retro fit such as yours, your kitchen cabinets are in place which might result in a vertical bust at the dishwasher and the fridge when you raise the net floor height. If you have stairs, your first riser may be reduced and be a possible code bust.

Vinyl floors or sheet goods are oftion put on top of luan, a thin smooth 1/8 to 3/16 thick plywood like substrate that is stapled to the subfloor (strange material, has a "cedar" type smell). If you have this, and strip the luan and the vinyl, you will gain this combined thickness which will then be offset by the durrock (or whatever overlay you use), tile, and thinset. Figure this out now and determine if you will have a cabinet bust and figure it into your pain.

My house? I put 3/8" AC plywood glued and screwed over the OSB subfloor followed by thin set and tile. Staggered all the AC sheets each way so have 1/2 sheet overlay compared to the OSB substrate. OSB was screwed to joists firsts followed by the AC. I used 12x12 tiles not one crack. Smaller tiles will crack less compared to big ones. I used 3/8" AC because I had to plane out with hardwood floor in adjacent area and refused to have a reducer.

The Ditra is good stuff. I have no experience using it over wood. We only used it on basement slabs to prevent/reduce cracks in the slab from telegraphing thru tile.

 

[PeterT]

Can I put the 1/4" cement board right on top of the linoleium? If so, just screw it down? Then thinset and tile?

If the linoleum is sound and flat, there is a thin set mortar you can use to go over it. I wouldn't recommend it though. I would use the 1/4" backer board or 1/4" cement board, with the tile and mortar, it would probably add about 1/2" or so.

 

[jhelrey]

They suggest thinset between the two but if you screw every six inches where the circles are, you will be fine. Just make sure you screws are waterproof and go through 1/4 and the subfloor. I've done both with no issues.

Also, put fiberglass tape over seams and thinset that as well. It will help keep the movement down to nada.

 

[PecosBill]

It is very important to use thinset between your backerboard, and your substrate, when installing floors. The reason isn't what most thing though. The thinset fills any voids, thus keeping the backerboard from bouncing and working the fasteners back up and popping your tile.

As to installing directly over "linoleum", that is possible, but not recommended, especially if particle board OSB, or MDF, are used as underlayment under it. These underlayments are a nightmare under ceramic. The key to correctly installing tile is to remember that tile and grout do not move. If you are going to try and adhere to a substrate that might move, you need a flexible mortar system, like Mapei's Kerabond/Keralastic, but even these only remedy tiny amounts of movement, not the swelling that is possible with substrates like particle board. Backerboard is extremely cheap insurance.