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.
The advantage to sealing new concrete with a cure and seal is that the concrete does not have time to get dirty or stained. If a cure and seal is not being used, then you should allow the concrete to cure for 2-4 weeks. The industry standard is 28 days but that depends on the climate and mix of concrete. It is important to wait and not to seal new concrete too soon. Trapping moisture in the surface will likely lead to a premature failure of the sealer.