Flooring Tile - mortar mix

Hey Guys,

I'm getting ready to do another tile job, and this is the first time to set tile on hardwood floors, I'm going to use the backboard, but my question is the mortar what have you guys found best for this type job. I saw several different adative that you can add to the thinset mortar to make it better, but what is better and is it worth the 30.00 per two bags of thinset?

Thanks
Chris

Hi
I don't want to ruin your day or anything,,but you can't put the tile over hardwood floors...even putting hardiboard on top won't work...the hardwood is too un-stable and will buckle..just from the moisture in the thin set...and you will end up with either cracked joints..or cracked tile. Sorry..that hardwood has to go first.:(

Adanac's right... when I removed the slate some former owner had installed over my harwood entry, it took maybe 10 minutes to pull up all the tile and scrape off the dried thinset. It just won't hold. Of course, in my case, this was a good thing! the wood floor is still beautiful after refinishing, it's been 9 years.

Thanks for the reply guys, that is really bad. I know I don't have the resources to pull the floor up it is over 300 square feet. So let me do some begging here, can I put down 1/4 plywood with Liquid Nails and then Doarock on top of that with Mortar? If nothing else I will have to go with Carpet, but tile is by far more enjoyable with the big dogs we house.

Thanks
Chris

How thick is the hardwood? If it's the thin stuff you should be able to pull up the floor in an afternoon. If that's not an option I would suggest putting down 15# roofing felt paper over the hardwood and thinset the backerboard to the paper. This will keep the moisture from the thinset off the hardwood and will also give you a slip plane that will keep any shifting in the subfloor from transfering to the tile. I wouldn't worry about the additive in the thinset between the felt paper and the backerboard but I would DEFINITLY use it between the tile and backerboard.

Hi
Yes..but you still have to screw it down..and the screws will go into the hardwood..which means the top layer will move with the hardwood. The slip sheet may help as kliot has mentioned...but I've seen tile floors lift 4 inchs that had hardwood underneath.

Hey...why not just have the hardwood re-finsihied?;)

I truely thank each of you for your input, I think for now the best thing to do is go with Carpet and then plan to refinish the hardwood later. i really didn't want three different types of flooring in the house, but I will have to deal with it. I would have to do alot of repairs to the hardwood and I don't have that much time before we go to closing on the house. I really am glad that I asked the question about adhestive or I would not have known about this huge problem.

Thanks so much,
Chris

Just a thought, but what about covering the old hardwood floor with a new wood laminate floor?