Bathroom wall tiling questions

We just had a surround removed from our bathroom, and are about to have the tub/shower area tiled in two days. There's existing insulation (fiberglass maybe?), but I don't know if our contractors put in a vapor barrier before they installed the Durock. Is this step essential? What happens if there is no vapor barrier? They did spread some thick grey material on top of some of the Durock.

Also, our contractors plan to do the tile job in one day. When I queried them, they told me "it's not complicated". However, I thought I read somewhere that bathroom wall tiling takes two days to complete. Are there any conditions under which it's ok to do everything in one day? We want to make sure we're paying for a quality job that will stand the test of time. The contractors live a distance from our home, so traveling to the job is probably a litle time-consuming.

Your advice is appreciated!

 

yes they have to let the adhesive dry for 24 hours then come back and grout the tile and then that has to dry for 24 hours.

 

There are topical "spreads" that one can use to waterproof.
One is called RedGuard and I believe it turns red after it dries.
But it should be over the entire shower area.
Vapor Barriors are important. You need one. Either roofing felt/plastic behind Durock, or redguard on top.

There are additives one can add to the thinset to make it a "quick dry" mortar, allowing "professional" (pronounced: very fast) tilesetters to set and grout on the same day.
Whereas in comparison, it took me four non-consecuative days to tile and grout MY bathroom.