Sizing Your Truck or Trailer for an Insulation Machine, Material and Accessories

How much insulation can you carry in your trailer or truck for each job? If you are installing blowing fiberglass you need less storage than you will for cellulose. Cellulose has less coverage per bag which requires a larger trailer or truck.

Truck or Trailer?

The most important part of this question is answered by your State’s regulatory requirements regarding vehicles and their inspections. Commercial trucks may need to go through weigh-master stations and are subject to mechanical inspections. The State of Michigan is very accommodating. You neither need annual vehicle inspections nor weigh-master stops for a typical 24 foot truck. That is not the case in all states. The State of Illinois requires strict annual vehicle inspections, for any vehicle used commercially. So, this is the first question you need to determine. “Are you willing to comply?”

Trailers are far easier to maintain. A trailer full of cellulose/fiberglass, a machine and ladders would not even max out over the typical 7,500 pound limit. This is not to say that a trailer is exempt from maintenance and weight limits.

Determining the size of truck or trailer

Whether you blow in cellulose or fiberglass, a decent-size trailer will provide you room for your machine, ladder, hose reel, generator and material for at least 3 average sized homes (i.e., 1,200 sq ft). How did we arrive at that? The calculator below serves a couple of different purposes:

  • Calculates the number of bags you need for a particular job.
  • Calculates the size of trailer/truck (internal dimensions) for determining the size you need.

[gravityform id=”5″ name=”Coverage Calculator” tabindex=32]

*Average coverage charts: [per 1,000 sq.ft.]


  • Loose Fill Attics: R-30, 9.5” deep, (30lb. /bg) = 30 bags
  • Dense Pack Sidewalls: R-13,  2” x 4” wall, (30lb./bg) = 27 bags
  • Dense pack Sidewalls: R-20, 2”x 6” wall, (30lb./bg) = 40 bags

* 30lb. bag dimension = 14” x 15” x 28” long or 3.4 cu./ft. per bag


  • Loose Fill Attics: R-30, 10.5” deep, (33lb./bg) = 13 bags
  • Dense pack walls: R-13, 2” x 4” wall, (33lb./bg) = 13 bags
  • Dense pack walls: R-21, 2” x 6” walls, (33lb./bg) = 21 bags

* 33 lb. bag dimension = 8”x 20”x 38” long or 3.5 cu./ft. per bag

Note: *Average bag weight, volume, and coverage. Individual manufacturer’s specifications may vary.