Due to circumstances we need to have the concrete floor of a new kitchen extension laid in two separate halves. I am worried that when I later stick ceramic floor tiles down, there might be future problem with cracking at the joint of the two floor halves. (extension size 5m x 5m) Should I do anything at this stage to reduce problem? (eg. leave bits of rebar protruding when first half laid, to tie the two halves together)??