tiling over tongue/groove sub floor
#1

My kitchen sub floor is .75" thick x 3.5" wide tongue and groove boards. With the linoleum removed, the subfloor is about 3/8" below the hardwood where it meets the hallway and living room.
Prior to tiling, do I need to put another layer of underlayment over the tongue/groove sub-floor? If so, what thickness should I use? And, what is the best way to transition into the hardwood, given the tile will end up higher than the hardwood?
-julie
Prior to tiling, do I need to put another layer of underlayment over the tongue/groove sub-floor? If so, what thickness should I use? And, what is the best way to transition into the hardwood, given the tile will end up higher than the hardwood?
-julie
#2

1/2 inch ceramic tile backer board should do the trick...glued down with the same thin set you will use for the tile, and screwed down also. Since you are butting up to your existing hardwood floor, you can use a hardwood threshhold here to reduce the difference in height. Or you can use marble, or use ceramic reducers from http://www.schluter.com.
#3
You will want to use hardi-backer board, anytime you are putting C-tile over a wood subfloor. http://www.hardibacker.com/hardibackerinstall.htm
It comes in ¼" & ½". You will need a transition threshold of some type, with a ¼" gap on the hardwood side and the c-tile side to allow for expansion of the wood. If you don't, you will watch the wood pop or you will see the c-tile pop, and I do mean POP!
It comes in ¼" & ½". You will need a transition threshold of some type, with a ¼" gap on the hardwood side and the c-tile side to allow for expansion of the wood. If you don't, you will watch the wood pop or you will see the c-tile pop, and I do mean POP!