QUESTION

I am laying tile in a basement half bath. I need to fill and patch a hole in the concrete that is about 18" x 18" the existing concrete around it is about 3"-4" thick. I know the standard wait time for concrete is 28 days, but I was wondering if there is a method or a product that I can use that will speed this up significantly. I would love to start the job a week after I pour the patch if possible.

ANSWER

ANSWER - There are rapid setting concrete mixes that can be purchased like QUIKRETE® Fast-Setting Concrete Mix.  It sets up within an hour, but doesn't stop shrinking right away.  If you heat up the area, some manufacturers state that for every 18ºF above 70ºF (10ºC above 21ºC), portland cement based materials take half as long to cure.

There are liquid applied waterproof/crack isolation membranes that allow you to go over new concrete within a few days. There are uncoupling systems where you can go over new concrete the next day.  There are some higher quality flexible thin-set mortars that allow you to install sooner over new concrete.