fiberock underlay

[markmark]

i have a 5/8 subfloor and am thinking about using 3/8 fiberock over top of this before 12x12 tile. joists are 2x8 with apx 8 to10' span. has anyone had anyexperience with this...or suggestions?
thanks mark

[jimbo]

That may be marginal. I would ask over at www.johnbridge.com (http://www.johnbridge.com), because they are the tile gurus and can answer this question with certainty.