mesh net to help keep crawlspace insulation from sagging
I had to insulate a crawlspace with joists at 24" on center, no-one seemed to have insulation hangers that length locally, and there was some urgency about getting it done. I had some 1" roofing nails and a ball of mason twine. I started in one corner, drove a nail part-way into the first joist a foot or so from the end and tied the end of the string to it, then drove the nail the rest of the way. I then went to the next joist, drove a nail part-way, looped the string around it, pulled it tight, and drove the nail home. I proceeded like this across the space, then repeated the process a couple of feet further along the joists. I went back and forth like this until I got to the far end of the house. The building inspector approved it, and the insulation was all still in place five years later when I went under there again. I would have used insulation hangers if I had been able to find the length I needed at the time, though.