***glass floor in my house what thickness glass do i use***?

Hi all im constructing a glass floor in my home..the panel sizes are 600mm*600mm I have found a supplier of glass who has cert BS-6206 from abroad, what thickness does the glass need to be laminated to (ie two 12mm glass panels) as the frame builder said 14mm is enough but i hear that this is not the case..also once i get my glass is it poss to be able to cut the odd sizes myself..please help..also im i right in saying laminated safty glass can be cut. thanks all..glass geek