Floor Insulation
The area over the crawl space was insulated with R25 unfaced insulation. House wrap was stapled to the bottom of the floor joist to hold the insulation up. If you don't want to do that for your project, then insulation support wires could have been used to hold up the insulation. Here is the progress after the insulation was installed. However, the area over the basement/storm shelter will not be insulated until later when it's ceiling is completed.
Decking
First off, sorry we forgot to get a picture before covering it up with plastic. The 3/4 inch tongue and grooved OSB subfloor decking was glued down to the joist with Liquid Nail adhesive and screwed down. Screw spacing was 6-8 inches apart with 1 3/4 inch screws and plastic was put on it to protect it until the roof is put on. With the sheeting running perpendicular to the joist for strength it took 3 rows with 4 sheets each.
