Depends on how many plants, size of plants, strain, and plants age, ie more at the end then at the start.
I would that if your growing weed in your house that if anyone ever comes over they will know your growing pot.
So yes they smell kinda alot.
No i dont think the smell can get threw even thin drywall. It doesnt breathe much.
Best defence is i feel a carbon filter pulling air from the grow area. This makes the grow space a vacuum and smell wont even try to get out, just goes to filter.