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12 TJI 19 on center seem plenty strong to me. So does the 3/4″ T&G OSB. I think you are good to go with what you have. Stomp on it a couple of times. No deflection? Then your good to go.
This is what I would do:
1. Install an isolation membrane over the OSB. This is a rubber/neoprene/pvc/ type of material. One side is rough so you can tile over it. I used one last week called ProtectaShield or something like that which was a $1 a foot, and was like Peel and Stick you would put on a roof, but coated with fabric on the upside that takes chalk and thinset real well.
2. Tile over the isolation membrane as ususal. This solves your elevation issue as well.
One note: The ProtectaShield or whatever they call it is really, really sticky, and is a bear to install alone. The stuff loves to stick to anything, and especially itself. You will never, ever, get it up. So be happy with your tile, or be prepared to tile on top of it in the future. You won’t ever get it up.
A really good site hosted by Tile Expert Michael Byrne is located at http://www.jlconline.com/forums/tile/. You might want to pose your question there.
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12 TJI 19 on center seem plenty strong to me. So does the 3/4" T&G OSB. I think you are good to go with what you have. Stomp on it a couple of times. No deflection? Then your good to go.
This is what I would do:
1. Install an isolation membrane over the OSB. This is a rubber/neoprene/pvc/ type of material. One side is rough so you can tile over it. I used one last week called ProtectaShield or something like that which was a $1 a foot, and was like Peel and Stick you would put on a roof, but coated with fabric on the upside that takes chalk and thinset real well.
2. Tile over the isolation membrane as ususal. This solves your elevation issue as well.
One note: The ProtectaShield or whatever they call it is really, really sticky, and is a bear to install alone. The stuff loves to stick to anything, and especially itself. You will never, ever, get it up. So be happy with your tile, or be prepared to tile on top of it in the future. You won't ever get it up.
A really good site hosted by Tile Expert Michael Byrne is located at http://www.jlconline.com/forums/tile/. You might want to pose your question there.
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Lay 1/4 inch Hardibacker with mastic under, allow to set.
Tile with Flex-bond, and your tile should fair-out fine... having the tile up 1/8th will save the wood floor edges from wear at the transition.
*the 19.2 inch spacing is teh problem.. especially with a 12 inch tile.. you will get cracks at teh plywood joints due to the deflection of the plywood..lay the 1/2" underlayment ply.. so you have the recommended 1.25 inch total..the hardibacker and the durock have no deflection resistance...check out the michael byrne site though.. i heard him speak at JLC live.. good tile man...you can lay shims under the last couple pieces of oak to transition for the 1/8 inch...
*Caleb,Mike's right, the joist spacing is the weak link. Nail the 1/2" concrete board to the subfloor & tile away.You should use concrete board in a bathroom or kitchen application because of the chance of water infiltration from different fixtures leaking or overflowing over the years. The concrete board can tolerate that water better than plywood. Your idea for the transition sounds like a good idea. Make sure you have a tapered shim under the whole 5" and not just under the edge you want raised.
*caleb... its better if you don't lay tile to wood; I suggest a hardibacker or duroc,(I prefer hardibacker)its not a bad idea to lay plywood over the t&g, but top that with a cement board.also, before you attach your cementboard to your underlayment, trowel a 3/32 bed of latex-modified mortar. then attach your board with 3/4-1 1/4" corrosion resistent nails or screws. also,concerning your transition...your idea will work; you may also check with your local flooring co.many hardwood flooring manufacturers, make transition pieces that cover the edges of both floors, and look quite nice when finished.---roger
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I've got about 500 sq feet of ceramic tile to lay in my house (new construction). This includes the kitchen, entrance way, some hall ways.
I'm trying to determine what to put down as an underlay. The subfloor is 3/4 T&G OSB, glued and nailed to 12" TJI's on 19.2" centers. The TJI's were designed for a deflection of L/480.
Around here, almost all tile seems to be layed on a plywood underlay as opposed to a "cement board".
The tiles will be a 12 x 12 ceramic tile.
The recommendation I've gotten from local tile stores is to use a 5/8 fir plywood (expensive).
What are the advantages of using a cement board instead of plywood?
Plywood seems easier to work with, but I'm unclear on the disadvantages.
If I go with plywood, would a 1/2 pine plywood screwed down in a 4"x4" pattern be good enough.
On a related note, the tile will be meeting a 3/4 inch oak floor. With a 1/2 or 5/8 underlay and the tile, the top of the tile will be between 1/8" and 1/4" higher than the oak How would you transition between the two? Right now I'm planning on sloping piece of oak 5" wide. Will a 1/8" to 1/4" slope over 5" be awkward to walk on and over? This transition will be an a heavily used area, the border between the kitchen and the family room.