I am planning to set tumbled marble mosaic tiles (2 x 3) on bathroom walls Not in the wet zone. I have fastening densshield to the bwall studs and have discovered some dips and bows. What can I use to level the densshield? Will duoflex 90 mastic work? I am planning on using this to set the marble. Is mastic the right adhesive to use on densshield?
You should correct the bows before you install the wallboard, not after. Is it done already?
The directions for your mastic claims to be OK for marble tiles installed on walls. I highly recommend you not using it though. You should be using a good quality white thin set mortar. These come ONLY in a bag, in powder form. As for does your mastic bond to Dens? Only the manufacturer can answer that, what did they say? Again though, use thinset. It's much better and much cheaper too.
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.