Is kerabond suitable to be used over Ditra for a natural stone bath floor? I was told to mix it with water and not without the additive kerilastic..

Mapei's Kerabond is a premium unmodified thin set, so it's a great choice for any installation over Ditra.

Have you checked that your subfloor system is suitable for natural stones tiles? The requirement is different from ceramic and porcelain tiles you know?

Jaz

The underlayment is 3/4 t&g with a layer of 3/4 ply that is screwed down heavily. The ditra mat is on top of that.. The framing is 2X8.. 16 in. center. The tile is 12 X 12 and is a small area 30 sq ft. Any additional comments will be greatly appreciated..

By 3/4 t&g I guess you mean 1" x ? plank subfloor. That and the 3/4" ply should be fine as the subfloor and underlayment. 16" o.c. is common, the 2x8 may be marginal. You didn't mention what the span of the joists is.

Jaz