1/4" hardie board instead 1/2" around bathtub - why not?

[Curiousv]

I know ideally we should use 1/2" cement boards around bathtub but I am getting 1/4" boards almost free...so wondering what will happen if I use them ?

 

[WorthFlorida]

1/4" board might flex some if pushed on to and it won't be flush to the usually 1/2 drywall. Most walls are not flush and straight so the board will flex more to the contour of the wall. Depending on type & size of the tile and using thinset to built the 1/4" it may work. You can alway use blocking between the studs to stiffen up board. 1/2" cement board is not that expensive (~$11 per board) and it takes about six sheets to do a bathtub surround.

 

[Sponsor]

 

[Jadnashua]

Hardie is the only manufacturer of a cbu that allows their 1/4" panel to be used for a tiled wall (16" OC maximum). It's stiffer than a conventional cbu. FWIW, there are two generic classes of cbu: true cement boards, and fiber-cement boards. Hardiebacker is a fiber-cement board. The fibers (cellulose) make it stiffer than a 'plain' cement board. Make sure to install it per the manufacturer's instructions, as if installed incorrectly, the board could absorb moisture and swell the cellulose. Installed properly, it's fine.