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.
Insulation crawl space floor joists.
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.
Cover the walls with insulation from the sill plate to the plastic covered dirt floor.
Floor insulation for moderate climes popular reads.
Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates.
The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall.
If vents are not present in your crawl space insulate the walls instead of the joist bays.
When the basement or crawl space has vents installed insulating joist bays.
Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.