I'm building a BBQ Island that will be framed in steel studs with cement backer board. My wife is interested in having me install Hardie Siding (technically Hardie Square Channel Siding) to finish the sides but I'm unsure how to best install fiber cement siding to cement backer board (I've only ever installed on wood substrate).

What is the best way to affix the siding? Can I just use the same fasteners used for wood substrates? Is there a better type of substrate other than cement backer board (needs to be non-flammable)?

Appreciate any and all answers!


1 Answer 1


When in doubt, read the fussy manual.

Applying James Hardie® Siding over Continuous Insulation and Non-Nailable Substrates

Method 1: Applying Hardie® Siding Directly through C.I. and Non-Nailable Substrates 1 inches thick and less:

Step 6: Ensure the Fasteners selected are available in the necessary length

ii. For metal studs (with screws):

The length of the minimum #8 screw shall be increased as necessary to ensure it will penetrate through the minimum 20 gauge metal studs by 3 full threads when applying James Hardie siding directly over max 1 inch thick non-nailable substrates; screw head diameter shall be as required from Step 5.



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