Can someone explain to me how cement backerboard underlayment works?

[steppinthrax]

I just covered my kitchen floor in James Hardi cement backer. I notice the floor dosen't creek as much anymore. How does this stuff actually work and why can't I just put the tile directly on the plywood floor?

 

[sohcrates]

wood expands and contracts with moisture. cement board (or hardibacker) is cementious and effectively stiff.

it's the perfect tile surface!

 

[vi edit]

Moisture, mold, and rotting resistance. Plus it's a better surface for the tile grout to adhere to.

 

[Greenman]

A lot of floor creek and squeak is due to lose nails and blocking, just driving all the nails down will help. Did you set the hardibacker in thin set morter or just nail it down?

 

[steppinthrax]

Originally posted by: Greenman
A lot of floor creek and squeak is due to lose nails and blocking, just driving all the nails down will help. Did you set the hardibacker in thin set morter or just nail it down?

The floor squeaked considerbly before I tore up the old floor and old linolium tile. I then screwed down some lose nails. I laied thinset and planted the backerboard ontop of that. I noticed the floor quieted down considerbly but on the edge of one side of the floor there is a little creek but much less then before.

 

[amdskip]

Yes you need the separation to prevent tiles from cracking and all that moisture stuff. I'm in the process of laying a bunch of tile right now. Feel free to ask if you have any questions.

 

[WarhammerUC]

nice.. im in the process of kitchen remodeling.. is this a lot more expensive?

 

[Vette73]

If doing tile for floor look up Ditra. Its what i used and a lot of pros use now as well.

Or search john bridge forum for a great tile forum.

 

[sohcrates]

Originally posted by: WarhammerUC
nice.. im in the process of kitchen remodeling.. is this a lot more expensive?

3x5 panels are about $10

it's pretty much necessary for any modern tiling project. unless you are going over a concrete subfloor or something

 

[T9D]

Plywood is not porous enough and flexes to much. Tile won't stick well to it. And if even a little moisture gets under it all the tiles will come up.

You should have screws in the backboard also not just thin set. Really don't need thin set at all except on top of it which is under the tile.

 

[Greenman]

Originally posted by: steppinthrax

Originally posted by: Greenman
A lot of floor creek and squeak is due to lose nails and blocking, just driving all the nails down will help. Did you set the hardibacker in thin set morter or just nail it down?

The floor squeaked considerbly before I tore up the old floor and old linolium tile. I then screwed down some lose nails. I laied thinset and planted the backerboard ontop of that. I noticed the floor quieted down considerbly but on the edge of one side of the floor there is a little creek but much less then before.

I'm impressed! Most people just nail the stuff down and hope for the best. Your floor should last forever.

 

[WarhammerUC]

Do you have pics ?