Replies

1. 
   Barry_ | Dec 17, 1998 07:33pm | #1

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   According to Michael Byrne, author of Taunton's Setting Tile, you can apply tile to just about any surface, including plywood. It just needs to be stable.

1. 
   Scooter_ | Dec 18, 1998 12:40am | #2

   *I would lay an underlayment of backer board. The tile will not hold very well to plywood, and especially plywood with a finish on it. I would use ganvinized screws and thinset to apply the backerboard, and lay the tile on top of that.Mike Morgan

2. 
   Guest_ | Dec 18, 1998 06:33am | #3

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   Michael's book aside, I would never, never, never set tile directly onto plywood. Okay, so you have built the rough top securely, what about the expansion/contraction of the wood? You say plywood is dimensionaly stable? Okay, but when you have loose grout (a symptom of loose tiles) you will have learned a good (expensive, too) lesson. In the very least, I would suggest a tile underlayment glued and screwed to the plywood. I use an organic mastic troweled across the whole surface, not just spotted. I use a 1/8" V-notch trowel. Thinset, in place of mastic, should be acrylic modified. Thinset mixed with water breaks bond with the plywood.

   Keep in mind, tile set over underlayment board will mirror the imperfections of the plywood base, this is one reason a full mortar setting bed is superior.

3. 
   DJA | Dec 19, 1998 06:31am | #4

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   Carole:

   If your coutertop is level then I would use cement backerboard over the plywood. If the countertop is not level..or you have height differences between plywood sheets then you need a mortar bed. Assuming your sub-base is good...comb out thinset with a 1/4 inch notch trowel just like you would for tile. Set the backerboard and screw it down. If you are not installing a waterproofing membrane you need to use backerboard or other galavanized screws...drywall screws will rust. If you are installing a waterproofing membrane such as Nobleseal TS, this goes next....thinset, then membrane. I would recommend using thinset over mastic to set your tiles as it is much stroger in compression. Use a thinset with a powdered latex already in it or mix your thinset powder with a liquid latex additive.

   Good Luck...Dave

1. 
   Tripp_Huey | Dec 19, 1998 07:29am | #5

   *I agree with Dave. You need to set your tiles on a concrete backer board (Hardee, Durock, DensShield, Wonderboard, etc.) instead of the existing plywood top. Plywood can be used and will give good service in a light residental setting, but the system Dave described will withstand much more use. The plywood system Byrne discussed in his book was NOT coated with shelac. Any coating would inhibit a proper bond between the tile and substrate. Tripp

4. 
   Guest_ | Dec 20, 1998 07:12am | #6

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   Dave,

   Just curious, why do you need to thinset the backer board to the plywood? Wouldn't screwing it every eight inches be good enough?

   ...Asks the man who just put 1500 dollars worth of hand-made tile on top of 3/4" HDF that has 1/2" backer board screwed but not glued to it...

   Steve Zerby

1. 
   Guest_ | Dec 20, 1998 09:25pm | #7

   *Hardibacker comes in a 1/4" thickness.  While not havingthe mass of standard 1/2" backer board, it seems to be a it harder andmore rigid.  Also, I believe, it is fiber impregnated rather thanbeing the fiberglass mesh / cement sandwich.  Any thoughts/experiencewith the material?  I am considering using it as a underlayment for1/4" thick marble.  The subfloor is ¾” T&G supported by2x10 16” O.C.  With the ¼” backer, ¼” marble, and somemodified thinset above and below the backer, the floor thickness wouldpretty much the same as adjacent ¾” hardwood floor rooms. Hardibackerweb page     

5. 
   DJA | Dec 20, 1998 10:03pm | #8

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   Steve:

   Not to worry..your tile will be fine. Thinset assures uniform bond to the substrate over the entire installation but it sounds like you did a good job screwing it down. A good solid base that limits deflection is the main concern.

6. 
   Guest_ | Dec 23, 1998 10:40am | #9

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   Hardibacker is a very good material for tile backer board. I use tons of it. The 1/4" T eliminates the problems with thresholds, doorways, dishwasher heights, etc It is much more stable than the other backerboards. I'd recommend it to anybody. Just be sure to wear a dust mask when cutting it. I use a 4" diamond blade.

   (Matt G.; what is &frac" ?)

1. 
   Guest_ | Dec 25, 1998 01:47am | #11

   *re: (Matt G.; what is &frac" ?) It *was* a fraction like 3/4" or 1/4" until it got munged when the HTML code was converted from Netscape Composer to the fourm text window.Thanks for the info on HardiBacker. The sales info says that you can cut it by scoring it and then snap it like drywall???? I guess I'll find out.

7. 
   Carole | Dec 25, 1998 01:47am | #10

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   In installing ceramic tile counters, what is the best underlayment? The surface is plywood which has been coated with shellac. Can the tile go right over this?