I'm in the process of redoing my kitchen and have to remove the old floor down to the studs do to some water damage. I am going to use tiles for the floor with cement backer board but don't know if I need to put plywood down before the backer board or can I just put the cement boards on the studs and go from there.
I'm thinking you need to do a whole lot more research before trying to do this.
Studs are in a wall, joist are what holds up the floors.
Tile board has 0 top load strength. It would just shatter it walked on with no support under it.
To tile a floor and not have it fail you first have to figure out if the joist are strong enough to support it.
We need to know the width, spacing, and free spans.
I prefer to use Advantech for my subfloors. It's not effected by moisture, is not going to delaminate and is super flat and strong.
You need to use construction adhesive on top of the joist and nail or screw it every 6".
I like to lay 1/2 A/C underlayment rated plywood over that, but 3/8" will work.
It's laid so the seams do not line up with the seams below and needs to be attached every 4" on the edges and every 6 to 8" in the field.
Never nail into the joist when attaching the underlayment.
Then a layer of 1/4" tile board set in a thin bed of thin set.