Flooring concerns

[Yogi]

Hi,
Internal plastering of the walls in my building is almost done. I had informed the contractor that granite flooring will be used and hence he has left space for skirting and has not done the lime plastering till the bottom. However, i am thinking of going for vitrified tiles now. What changes needs to be made if i need vitrified flooring since the granite thickness and vitirfied thickness are different? Appreciate suggestions from all of you...