Block off plate

[Jan Pijpelink]

I plan to install a block off plate within the next few days.
I bought Hardiebacker cement board for a different application and have a piece left. Covered with sheet metal, can I use this board as a block off plate?

 

[begreen]

Skip the hardibacker and just use the metal. Stuff some kaowood or roxul behind the blockoff plate.

 

[Jan Pijpelink]

Skip the hardibacker and just use the metal. Stuff some kaowood or roxul behind the blockoff plate.

Thanks.