I am having my kitchen& laundry room redone with a ceramic tile. Currently have a linoleum floor. I am wondering which underlayment is most recommended. One contractor plans on using 1/4" Wonderboard, while another contractor wants to install on a wire/mortar bed. The difference in cost is significant ($3,000 -vs- $3800) so I'm wondering if it's worth the addl. cost for the more expensive installation. Both contractors are very experienced and highly recommended by others. My house is 10 years old and we have not had any problems with our current floor.
The advatage with the Wonderboard is taht it's only 1/4" high.
A less expensive option might be to install another 5/8 or 3/4 ply over the existing floor. The height differences do add up though.
I would think most of that difference is extra labor costs.
I'm not sure how high the wire/motar bed would be.
Life is an experience... Learn from it!