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R-49 is the common target for the roof or ceiling in cold and mixed climates. That is about 20 inches of blown fibreglass, 15 inches of blown cellulose, 16 inches of fibreglass batt or about 8 inches of closed-cell spray foam. Air seal the ceiling plane before adding any of it.
Whether you're quoting a job or planning a weekend, this converts square footage into realistic hours by material and difficulty.
With these inputs:
| Result | Value |
|---|---|
| Total labor hours | 15.2 hrs |
| Elapsed time with 2 people | 7.6 hrs |
| Working days (8 hr) | 1 days |
| Setup and cleanup included | 2 hrs |
| Labor cost | $836 |
| Labor per sq ft | $0.7 |
Hours = area × production rate for the material × difficulty factor, plus 2 hrs setup · Elapsed time = total hours ÷ crew size · Labor cost = total hours × hourly rate
A two-person crew blows a typical 1,200 sq ft attic in 4 to 6 hours including setup. Batts in a tight attic take considerably longer.
Crew rates commonly run $45 to $75 per person-hour depending on region, and most quotes are given per square foot rather than hourly.
Blowing an open, accessible attic is fast work once set up — the setup, the baffles and the hatch usually take longer than the blowing. What stretches a job is low clearance, obstructions, a long hose run from the truck, and having to install baffles in every bay first. The calculator asks about difficulty for that reason.
Considerably, for blown-in: a two-person crew with a truck-mounted blower moves far more material per hour than one person with a rental unit. Whether that matters depends on what your weekend is worth to you. For small areas and rim joists the difference is negligible.
Blown-in insulation genuinely wants two — one feeding the hopper and one on the hose. Attempting it alone means climbing down to reload constantly, which is where most of the time goes and where most of the mess comes from. Batts and board are workable solo.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.