I’m looking to build a flat sliding door, what materials should I use?

What are the best materials to create a flat, quiet, sliding door that I can use for noise reduction? Its 8 ft tall and one side faces the laundry room, that wont warp. I dont want the wood to bend due to heat & moisture changes.
Replies
Plain old 3/4" plywood should
Plain old 3/4" plywood should work pretty well. You can get hardwood faced plywood both to look nice and because it generally has more laminations and will stay flatter. But varnish well to help it say flat.
Otherwise, a sheet of cement board would work, but heavy and ugly.
can you order a door?
if you cant order a door or you are determined to build one, i would at least use 6/4 rails and stiles and same species for the panels.