After roughing out an arch on a custom tile shower. I don't know how to cover the curved arch on the bottom side. Duro-roc will not bend enough without breaking. Do I have to use another type material or is there a special way to prepare the duro-roc to make it bend without breaking?

Tony

1/4" Hardibacker will bend that much and its all you need for a shower wall. I frequently use Hardibacker in 1/2" sheets but that arch will never take any stress so 1/4" will do you.

I agree with ballenger, 1/4" board should do it.