Piggyback Attic Joists for Insulation Space
Our American Foursquare of 1904 has six-inch ceiling joists on the second floor, comprising an attic floor. There is no flooring there now. There is cellulose insulation to the joist tops in some spots, some bare areas showing in other spots.
I would like to add insulation to at least 12 inches depth, and maintain the ability to move around by piggybacking 2X6 joists on the existing, with OSB or plywood on top of that.
Is this a accepted practice, and is there a common process? May I simply glue and toenail the new joists atop the old, or should they be perpendicular?
Any other thoughts?