Here’s a clear, step-by-step write-up on the topic. If you’re looking to fill a standard 55-gallon drum with spray foam insulation (the type from a typical aerosol can), the answer depends on the yield of the foam — but a reliable estimate is between 12 and 16 cans .
Buy 15–18 large cans if you must use aerosols. Better yet, rent or buy a two-component foam kit — it’s cheaper, faster, and actually designed for filling large volumes.
→ round up to 12 cans (allow for overfill, waste, or settling).
Using the of 0.65 ft³ per can:
| Can size | Approximate cured foam yield | |----------|------------------------------| | Small (12 oz) | ~0.25–0.3 ft³ | | Large (24–30 oz) | ~0.6–0.7 ft³ |