MTcummins
In the Trades
You have no need for a waterproofing product such as Noble in your application. If you install those 32" tiles directly on wood, they will almost certainly pop off when the wood underneath expands and contracts. A product like Ditra will give some degree of waterproofing by default, but that is not its purpose... the sheet itself is waterproof, but the seams are not unless you go through an annoying process to make them water tight.
JW may not believe in uncoupling, but its a very simple concept that both Ditra and his own advised product Spider Web use... they separate the 2 layers that expand and contract different amounts and at different rates. Tile does not expand/contract much at all, and takes a lot of temperature change to do so, where wood expands and contracts a good bit at much lower temperature changes. The idea of uncoupling is to allow the 2 surfaces to move a bit, independent of each other. It is a concept that is thousands of years old... the oldest surviving tile installations in the world only survived because they decoupled the tile from the substrate.
The other way of doing it is to screw a similarly expanding/contracting substrate (such as CMU or Hardi or whatever) to the floor first, then attach your tile to that, so that they will expand and contract at the same rate. This can create stresses between the wood and the backer board, but usually is not a problem unless there is extreme temperature swings.
Both methods work well and have been fairly well proven. I personally am a Ditra guy, but would be interested to see a Spider Web install sometime (I've never seen the stuff used, to date), and see how it holds up over time. Sounds like a good alternative in the price department (though once again, I find JW's Schluter pricing to be very off, I pay under $1.50/sqft for Ditra), and the ability to use all modified w/o voiding warranty is appealing. Generally I use modified under Ditra to wood (proper), and modified over to set the tile (voids warranty), and leave a few days before grouting, especially if setting smaller tile. Larger tile (which I personally don't much care for and almost never use), this could be more of a problem. VersaBond has worked well for me, as it is not as highly modified, so it dries a little better than others when sealed off like that.
NOTE that I explicitly stated that doing this will void your warranty. It's how I, and a number of other people, have successfully used Ditra numerous times, but it is not manufacturer approved.
JW may not believe in uncoupling, but its a very simple concept that both Ditra and his own advised product Spider Web use... they separate the 2 layers that expand and contract different amounts and at different rates. Tile does not expand/contract much at all, and takes a lot of temperature change to do so, where wood expands and contracts a good bit at much lower temperature changes. The idea of uncoupling is to allow the 2 surfaces to move a bit, independent of each other. It is a concept that is thousands of years old... the oldest surviving tile installations in the world only survived because they decoupled the tile from the substrate.
The other way of doing it is to screw a similarly expanding/contracting substrate (such as CMU or Hardi or whatever) to the floor first, then attach your tile to that, so that they will expand and contract at the same rate. This can create stresses between the wood and the backer board, but usually is not a problem unless there is extreme temperature swings.
Both methods work well and have been fairly well proven. I personally am a Ditra guy, but would be interested to see a Spider Web install sometime (I've never seen the stuff used, to date), and see how it holds up over time. Sounds like a good alternative in the price department (though once again, I find JW's Schluter pricing to be very off, I pay under $1.50/sqft for Ditra), and the ability to use all modified w/o voiding warranty is appealing. Generally I use modified under Ditra to wood (proper), and modified over to set the tile (voids warranty), and leave a few days before grouting, especially if setting smaller tile. Larger tile (which I personally don't much care for and almost never use), this could be more of a problem. VersaBond has worked well for me, as it is not as highly modified, so it dries a little better than others when sealed off like that.
NOTE that I explicitly stated that doing this will void your warranty. It's how I, and a number of other people, have successfully used Ditra numerous times, but it is not manufacturer approved.