We just got tile laid in our kitchen in the beginning of April . The grout is already cracking . We laid concrete backer board down our selves . I can not remember the thickness but I think it was a little over 1/4 in. Could this be the reason that it's cracking because our backer board was not thick enough ? If this is the case will the cracks get a lot worse and the grout start to crumble ? Or could it be due to the drying ? And is there any way to fix it or are we going to have to tear it up ? Please someone tell me I'm over reacting ! Thanks so much for the help !!