greetings, i am going to tile a kitchen island top. i will be using 1/4
inch hardi backer board on top of 3/4 inch plywood. what is the best way
to secure the backer board to the plywood? should i glue it down and use
screws or just screws? what type of screw should i use? should i tape
the backerboard seams? finally, what depth trowel should i use for the
mastic and what profile, pointy or squared.
thanks, cj

Backer board should be installed using screws and adhesive. I would
prefer to use 1/2 inch cement board. Use a 1/4" trowel for applying
the adhesive to be used for the Backer Board. I use Rock-On Cement
Board Screws. Tape the seams using fibreglass tape and adhesive. I
also apply a waterproof membrane to the Backer Board after it is
installed. I use the Kerdi system and it works miracles.

can you give me more info on the waterproof membrane? why would i need
it..i thought the backerboard was waterproof
thanks, cj

Newfie wrote:
Backer board should be installed using screws and adhesive. I would
prefer to use 1/2 inch cement board. Use a 1/4" trowel for applying
the adhesive to be used for the Backer Board. I use Rock-On Cement
Board Screws. Tape the seams using fibreglass tape and adhesive. I
also apply a waterproof membrane to the Backer Board after it is
installed. I use the Kerdi system and it works miracles.

"cj" wrote in message
...
greetings, i am going to tile a kitchen island top. i will be using 1/4
inch hardi backer board on top of 3/4 inch plywood. what is the best way
to secure the backer board to the plywood? should i glue it down and use
screws or just screws? what type of screw should i use? should i tape the
backerboard seams? finally, what depth trowel should i use for the mastic
and what profile, pointy or squared.
thanks, cj


I just use a layer of thinset (same stuff used to set the tiles), place the
cement board on top then nail or screw the board down.

Actually backerboard and thinset are somewhat porous (depending on the
brand), it's the tile and grout (sealed) that form the primary waterproof
layer. For a counter, a liner is unnessary.

A bathroom floor on a second floor might benefit from a liner or a basement
where moisture might come up from beloew.

"cj" wrote in message
...
can you give me more info on the waterproof membrane? why would i need
it..i thought the backerboard was waterproof
thanks, cj

Newfie wrote:
Backer board should be installed using screws and adhesive. I would
prefer to use 1/2 inch cement board. Use a 1/4" trowel for applying
the adhesive to be used for the Backer Board. I use Rock-On Cement
Board Screws. Tape the seams using fibreglass tape and adhesive. I
also apply a waterproof membrane to the Backer Board after it is
installed. I use the Kerdi system and it works miracles.