jmyszka wrote:
I am planning on installing 5/8'' bamboo flooring in my three story
townhouse. I just ripped up the carpet and pad on the second floor and
discovered the subfloor material is not wood, but rather something that
resembles cement board used for tiling.

Get rid of the crumble board. It would be huge mistake not to install
bamboo or any nice wood on a proper subfloor. By all means call
customer service at the flooring manufacturer for recommendations. They
will have the best advice you can get. You might get lucky and find a
nice solid plywood subfloor, and that is likely what the flooring
people would advise you to use. Good luck.

Joe