If vents are not present in your crawl space insulate the walls instead of the joist bays.
Insulation crawl space floor joists.
Where winter temperatures are extreme opt for insulating the walls and sealing off the crawl space entirely.
Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates.
It is important to secure insulation and cover it with a vapor barrier in order to prevent moisture and the mold that often follows close behind.
In those days common building practice was to insulate the floor above the crawl space and to leave the crawl space s wall vents open so any moisture buildup would vent to the outside a.
Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.
The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall.
Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances.
If the crawl space is ventilated which is ideal because it aids in the elimination of moisture then fiberglass insulation can be easily installed under the subfloor between the floor joists.
In moderate or dry climates without the threat of sustained subfreezing temperatures insulation between floor joists makes sense.