Ceramic tile

[Rambo]

Is it commonplace to put ceramic tile on the floor of a house that is not built on a slab??

[HayZee518]

My house is circa 1920's and I have a ceramic tile floor in my bathroom shower!
If the floor doesn't bounce or flex too much I would say go for it!

[dkpbxman]

Deflecto

This is a neat little calculator from the John Bridge Ceramic Tile forum, useful for when you are looking to put down tile on wooden floors supported by joists.

http://www.johnbridge.com/vbulletin/deflecto.pl

Enter the requested information and they'll tell you if your flooring system is appropriate for tile or stone. If not, you'll have to "sister" the joists or otherwise stiffen the floor. Ask them.

They're very helpful people and as many "Tile" professionals post there, they can answer any questions you might have.