Granite Countertop

Hi everyone! I'm replacing my bathroom vanity countertop with a 49" granite. Do I still need to put a plywood underlayment or just put the granite on top of the vanity cabinet? Thanks!

Depends on the thickness. If it is 2cm stuff, yes, it's a good idea. If it is 3cm stuff, it is strong enough without. Doesn't hurt, but sometimes is difficult to do as it really needs to be recessed, then the sink can be problematic because of the total thickness. Depends on the faucet.