Travertine Selection

I am purchasing a new home and am going to be ripping up the tile in the entry way, kitchen, and breakfast nook, they are all connected. I was wondering what type of travertine would be suitable. i.e sealed, unsealed. Or my preference. It will be me my wife and our two weimereiners.

 

I was also wondering if i need to install a vapor barrier? i have layed ceramic and porcelin tile several times and have never used it. I live in Phoenix, Arizona so it is extremly dry here?

 

Also what is the difference in laying travertine tile to ceramic tile. i have read some things about self-levelers and other products. if the concrete is new it will most likely settle, but not to drastically should i do something to protect it, or will a standard stone thinset do the trick?

 

Thank you for any advice