Storing stuff in unconditioned attics isn’t a great idea. Typically attic storage requires access to the unconditioned space via a big hole – usually attic stairs – which are hard to make air-tight or insulate well. Things that are stored in unconditioned attics don’t fare very well. Attics have really big temperature and humidity swings, which is bad for almost everything except insulation. Nevertheless, attic storage is a sometimes necessary evil.
- Low environmental impact of using exclusively cellulose insulation,
- All materials are readily available to anyone running a cellulose crew (plywood, cellulose),
- Possibly low expense if labor costs can be kept down (good access, not too many cuts or craziness),
- Fairly robust.
- Laborious. Yeah, holy crap laborious,
- Still has thermally bridging at the plywood joists,
- Cellulose (and all blown insulation) has a lower R value than foam and therefore requires higher platforms to achieve high R value.
- Efficiency. Probably a lot faster than joists,
- Almost no thermal bridging.
- Using foam has a higher environmental penalty (but polyiso is the best of the foams).
- High material cost.
Stuff that I often wonder about: