I don't know what the deal is on mastic. I used mastic (a good $$ grade
from a real tile supply house) directly on
plywood, and not a thing has budged in 23 years. This is a rental unit
that's had over a dozen tenants.
Also used in in the bath area, but a black seal coat was put down first.
Also, no defects. Same groat, no
maintenance at all.

I wonder sometime if the cement board thing is mostly marketing.

Bill

wrote in message
oups.com...
Thinset in water areas are the way to go.
Mastic works nice when you work from the
middle and go down. I found that with a thinset
applied the tiles will start sliding down the wall.

There ARE certain mastics that are waterproof, but
a nice thinset (if using the home depot
stuff use the flexbond) worked great for me.

Use the regular mastic on walls that arent going to get
water on it.


wrote:
A few years ago some of the plumbing had to be replaced in the bathroom
of the house I grew up in, and part of this was to remove some mosaic
tiles that were put down about 1974 using a mastic. Man, getting those
babies up was a great deal of hard work, and now that ceramic tile has
entered a project of my own, I find everyone pushing thinset. Is it
really better? If there were a bit of floor flex, wouldn't a plastic
mastic tend not to crack as much as a thinset cement? And with a bit
of mastic coming up between the tiles, wouldn't it keep water from the
plywood (yes, right on the plwood!), rather than continuing to suck it
down as a cement would after going through the grout?
Now the floor was 3/4" diagonal T&G with 5/8" plywood, so perhaps
flexing wasn't all that much a problem (I've forgotten the exact joist
spacing & depth, but 2x10 16" OC seems to stick).
Still, with all the effort needed to remove these tiles, why's
everybody now down on plastic mastic?