Does cement smell/gas off after a few hours?
I have never heard of concrete &quot;off gassing&quot;. It takes 28 days to reach is major compressive strength and to loose most of its moisture when curing properly, but the only thing I have ever know concrete to give of is moisture, lots of it, since water is one of the main components.
I have never noticed concrete/cement to have an odor that was a VOC concern. The materials that make up concrete are lime based or naturally occurring products. It has been around for centuries. I think the Roman Empire used concrete in some of their work. Seriously, I just found this out just a few years ago myself.