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Blown In Insulation - Easier, Cheaper than Batt Insulation?


Blown In Insulation

Blown In Insulation

Public Domain: State of Nebraska
Question: Blown In Insulation - Easier, Cheaper than Batt Insulation?
Blown in insulation seems the way to go for my walls (maybe attic, too). How does blown in insulation compare to other methods? I don't want to open up my walls just to install insulation!
Answer: Yes, blown in insulation is really about the only way to insulate existing, closed-up walls. As you say, the only other option is to go outside and start pulling off siding...or rip out interior drywall.

DIY Blown In Insulation?

Rent an insulation blower and do it yourself, you say? Consider this...

One reality of blown in interior insulation that is rarely mentioned is that it is an imperfect process. Its almost too much to expect cellulose fibers to pass through a two-inch wide hole and settle uniformly and completely all throughout a wall cavity. Especially in older homes, wall obstructions abound: criss-crossing electrical wires, plaster "keys", blocking, etc.

Blown in insulation is almost an intuitive process. Most insulation technicians are experienced at probing for blocking and wires, and know how to devise workarounds. Because the pros know how to intuit these situations, my advice is to let them handle it.

The Process of Installing Blown In Insulation

Here's the simplified version:
  1. The technicians drill holes: one hole about 12" from the ceiling, another hole about 3 feet from the floor. Since most studs lay 16" on-center from each other, you can expect these holes to be about every sixteen inches.
  2. Using an insulation blower, a technician forces cellulose or mineral fiber "loose insulation" into your walls.
  3. Walls are plugged, either with plastic plugs or with drywall compound or Spackle.
Will the insulation company paint the plugs? Only if you supply the paint and have pre-arranged this. Most likely not, since insulation techs are not painters. The real question: do you even want them painting your walls?

Blown In Insulation Materials

  • Cellulose - Shredded newspapers treated with fire retardant. Even though it's "paper" and sounds ineffective, it's actually a well-established insulating material. Not only that, cellulose settles better into the wall cavities. Downside: it becomes a problem when cellulose gets wet, because it takes a long time to dry out--if ever.

    In the video More Than Fish Wrapper, New York Times reporter Tom Zeller, Jr. visits National Fiber Co. to see how cellulose insulation is made. Owner Tom Hoch tells him that telephone books, tax forms, and newspapers all are used to make cellulose insulation.

  • Mineral Fibers - This means fiberglass and rock wool, a more expensive option than cellulose. Lighter than cellulose. Good: it stands up well to moisture and does not rot out.

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