4x6 Joists at 32" oc

This crawl space of 1970's construction has 4x6 joists at 32" on-center. As in other crawl spaces, I wanted an insulation method that does not reduce headroom, and has nothing to snag a passerby. A solution is related to that imagined for 4x8 joists, 48" oc.

The 5 1/2" joist depth does not support use of R30 insulation. There would be objectionable waste in compressing 10" batts to fit. Worse with R30, available materials from Johns Manville are in 48" length only. There is far too much material waste in cutting to a batt length of about 30". R25 offerings include batts 16", 19" and 24", in 96" length. In cuts here, there was only about 4" of scrap from each 96" batt.

The plywood is centered on joist faces with a nail gun, producing 1 1/4" ledges that support "sticks" or "battens." The installed cost of attachment lumber matches that of the insulation, but insulation placement is a tolerable one-man job. The result is clean and serviceable, and should be worth more to a homeowner than drooping, random lacing with wire or twine.