Insulation Batt Coverage and Count
Batts and bags from the net cavity area / coverage per batt and per bag, at a waste allowance.
Example
You enter
- Net cavity area (ft², less openings) 500
- Coverage per batt (ft², e.g. 10.67 for R-13 15 in) 10.67
- Coverage per bag (ft², from the label) 88
You get
- Batts (pieces) 47
- Bags 6
Details, formula, and sources
500 ft^2, R-13 batt (10.67 ft^2), 88 ft^2/bag -> 47 batts, 6 bags; a deeper R-21 bag covering 67 ft^2 raises it to 8 bags for the same wall. Count the batts to confirm a full fill. The label coverage governs.
net = area x (1 + waste%); batts = ceil(net / coverage_per_batt); bags = ceil(net / coverage_per_bag).
Batt insulation takeoff from the manufacturer's label coverage per batt and per bag, by name.
The area-over-coverage takeoff is public arithmetic; the coverage per batt and per bag come from the manufacturer's label.
Estimate. AHJ and licensed professional govern.
Field names used by the API: area_ft2, coverage_per_batt, coverage_per_bag, batts, bags
- Net area cavity area less openings, times the waste allowancetakeoff practice
- Counts batts = ceil(net / coverage per batt); bags = ceil(net / coverage per bag)arithmetic
- Label coverage coverage per batt/bag from the manufacturer's labelscope of this tile