their idea of sealing the foundation vents was to ... greatstuff foam the metal dampers?
should be mastic sealed 2" foam behind the door.
the 10 mil vapor barrier is also great stuff foamed? also a fail. all the plastic is supposed to be mastic sealed to the brick.
also, 10 mil is about 1/2 what I'd use. then again, you got a low price, it may work for your needs.
There seems to be a contest as to how thick the plastic sheeting needs to be. I am not aware of a national standard set by ADOPTED code. The first crawl space that I sealed was my parent's home, back in 1996. We used 6 mil at that time. It is still in good shape. As to the adhesive used, as long as you get good adhesion, you should be OK. I have never tried Great Stuff, but if it works, it should be OK. Just because it is not what I would use does not make it wrong.
Note that some locations may have adopted a code. If your location has one, you should follow it.
Drying the crawl space is the goal here, not running the price up or running the completion down.
Put some kind of sensor in the crawl space so you can monitor its condition. As long as it is dry down there, you are good to go.
If dampness resumes, then further measures are required.
and I need to change my spray foam recommendation to closed cell.
I've learned a few things in the time since this thread was started!
good advice you are getting here btw.
and as always...
best of luck.
Thanks to all who have posted here. You helped me a bunch! This thread is a good resource now if things don't work as expected.