Freight Class for Insulation
Insulation is mostly air, so it rates near the top of the freight class scale. A unit of 96 one-inch FOAMULAR foam boards, 4 × 8 × 8 feet and about 370 to 400 lb, measures about 1.5 lb/ft³, class 300. Big orders also meet carriers' light-freight minimums: XPO bills shipments of 750 cubic feet or more under 6 lb/ft³ as if they weighed 6 lb per cubic foot.
Foam board units
Owens Corning's FOAMULAR 150 data sheet packs 1-inch 4 × 8 boards 12 to a bundle and 8 bundles to a unit, 96 boards or 3,072 square feet, in a unit about 4 × 8 × 8 feet. At 120 to 130 lb per 1,000 square feet, the unit weighs about 370 to 400 lb. That is roughly 1.5 lb/ft³, class 300.
Fiberglass and mineral wool batts come in packs instead. Owens Corning's R-13 batts come 11 to a package covering 120 square feet, and ROCKWOOL's Comfortbatt R-13 comes 12 batts to a pack and 12 packs to a pallet. Pack weights are not published consistently, so weigh them.
Worked examples
Unit sizes and weights come from Owens Corning's FOAMULAR data sheets; the minimum charge rule from XPO's rules tariff.
Unit of 1-inch foam board — class 300
Owens Corning FOAMULAR 150: 96 boards (3,072 sq ft) in a 4 × 8 × 8 ft unit, about 370 to 400 lb.
48 × 96 × 96 = 442,368 in³ ÷ 1,728 = 256 ft³. Density = 370 to 400 lb ÷ 256 ft³.
1.4 to 1.6 lb/ft³ → class 300.
Three units with XPO's light-freight rule
Three of the same units: 768 ft³, about 1,150 lb.
768 ft³ is over 750 and averages 1.5 lb/ft³, under 6. Minimum billing weight = 768 × 6 = 4,608 lb at class 125.
XPO would bill about four times the real weight. Ask for a volume quote.
Light-freight minimums
Insulation is exactly the freight that carriers' light-freight rules were written for. XPO's tariff bills any shipment of 750 cubic feet or more that averages under 6 lb/ft³ as if it weighed 6 lb per cubic foot, at class 125.
Three FOAMULAR units are 768 cubic feet and about 1,150 lb. Under that rule XPO would bill them as 4,608 lb at class 125, four times their real weight. Ask about these minimums, or a volume quote, before shipping big insulation orders LTL.
Heat and fire
Owens Corning warns that FOAMULAR foam is combustible and should not be exposed to open flame or other ignition sources during shipping and storage. Its maximum service temperature is 165 °F, and it should not be covered with dark or clear sheeting in the sun, which traps heat. Kingspan adds that foam board stored outdoors should be kept in its packaging or under an opaque, light-colored tarp.
Mineral wool behaves differently: ROCKWOOL rates its Comfortbatt as non-combustible. Keep foam away from heat sources on the dock and in the trailer.
Check your insulation shipment
Enter the unit or pallet size and the weight. If the total is over 350 cubic feet, check the carrier's light-freight minimum as well as the class.
Density-based estimate. Some commodities carry a fixed NMFC class — check our freight class by commodity pages.
Estimated Freight Class
Density
1.5
lb/ft³
Volume
53.33
ft³
Weight
80
lb
1–2 lb/ft³ → Class 300
NMFC density scale (Docket 2025-1, effective July 19, 2025)
Pre-July-2025 table: class 400. Use it only if your carrier contract still prices on the old table.
Free PDF includes a watermark. Pro removes it & adds your brand.
Estimates only — verify freight class/NMFC and chargeable weight with your carrier.
Uses the 13-tier NMFC density scale (Docket 2025-1). See the full freight class chart.
Frequently asked questions
What freight class is insulation?
Foam board insulation usually rates class 300: a unit of 1-inch FOAMULAR measures about 1.5 lb/ft³. Batts and rolls are also very light for their size; weigh and measure the packs.
How much does a unit of foam board weigh?
Owens Corning lists FOAMULAR 150 at 120 to 130 lb per 1,000 sq ft at 1 inch thick, so a 96-board unit (3,072 sq ft) weighs about 370 to 400 lb.
Why is my insulation freight bill so high?
Often because of a light-freight minimum. XPO, for example, bills 750 cubic feet or more under 6 lb/ft³ as if it weighed 6 lb per cubic foot, at class 125.
Is foam insulation a fire risk in shipping?
Owens Corning says FOAMULAR is combustible and should be kept away from open flame and ignition sources during shipping and storage, and not covered with dark or clear sheeting in the sun.