Sorry for the double post, this is an addendum to my previous question. I am planning to re-tile the downstairs foyer. Since it's on the 1st floor of a townhouse with no basement I think there's cement slab underneath, but if I need backer board I need to purchase and make arrangements to cut (I don't own a saw yet). I'd like to take a couple tiles off to check, but how can I tell the difference between the two?
By your question it sounds as if you intend to re-tile the floor, if so it will be concrete and you be able t tile straight over it once the other tiles have been removed and the slab made good for tiling.
If you're laying tile on a concrete slab, you don't need to add anything, just lay the tile directly on the slab. You will need a cement-fiber board for vertical surfaces like walls. I like the Hardie products.
You won't be able to pound a nail into the concrete.
one is cement and one is gypsum.
