Size your attic upgrade before you buy: depth to blow or spray, coverage per bag or kit, unit count, and budget — computed offline in your browser.
| Type | Form | R / inch | Notes |
|---|---|---|---|
| Fiberglass batts | batt / roll | 2.9 – 3.8 | Lowest-cost DIY; loses R if compressed, damp, or gapped |
| Fiberglass loose-fill | blown | 2.2 – 2.9 | Calculator option; settles ~20%; prone to wind-washing at eaves |
| Cellulose loose-fill | blown | 3.2 – 3.8 | Calculator option; recycled paper, borate-treated; dense-pack also air-seals |
| Rock wool (mineral wool) | batt | 3.0 – 3.4 | Fire- and moisture-resistant; denser and pricier than fiberglass |
| Open-cell spray foam | sprayed | 3.5 – 3.8 | Air-seals; vapor-permeable; needs real depth to hit high R |
| Closed-cell spray foam | sprayed | 6.0 – 7.0 | Calculator option (DIY kits); air + vapor barrier; highest R per inch |
Highlighted row matches the selected calculator material. Values are typical cured / settled ranges; check the product data sheet for exact figures.