I have a shower and the grout on the floor has hair line cracks in it. The shower wall is fine, no problems. Upon looking closely at the grout I found that there are holes through out it. The holes don't seem too deep, the don't seem to be all the way through it more like bubbles in the grout at the time of the application.
Can I simply just cut out the grout from the hair line cracks or should I try to cut all of the grout from the shower base? Can I spread grout across all of the tiles even ones that I didn't cut the grout from? Will it bond?
Any advice would be greatly appreciated.