Howe much postage to send a postcard from US to Canada? As of September 2014, it costs $1.15 to ship a post card  internationally. If it exceeds 4 3/4 inches high or 9 1/4 inches  long, you will be charged the First Class Mail In â¦ ternational price. + 3 others found this useful.
Concrete is never truly done curing, but the minimum wait time should be 28 days. A slab typically cures at least 80% during that time. I suspect the manufacturer is asking you to proceed cautiously to avoid a lawsuit. If you (or your client) can wait that long, then wait the 120 (or more) days. But I wouldn't put any flooring on it inside a month.
Add your answer. How long does it take for cement/concrete to dry? I had a slab leak in my kitchen. A plumber came to my home and had to jack hammer a hole in the floor to get to the leak, after the repair was made he covered up the hole with cement/concrete. How long before we can actually walk on the area? I'm afraid to walk on the area if it is not strong enough, should we wait for 28 days?