How to Install Dry-Blown Cellulose Insulation in 5 Easy Steps

Matt Marandola
Written by Matt Marandola
Updated January 31, 2022
fully furnished attic apartment
Photo: Daniel Jędzura / Adobe Stock

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Dry-blown cellulose insulation (loose-fill or dense pack) is a great alternative to fiberglass insulation for the everyday DIYer. Unlike fiberglass insulation, there are fewer health risks involved. Before you get started on this project, make sure you have the right supplies and tools handy, and the right R-value for your project.

R-Value specifies insulation level, or the insulation’s ability to resist heat traveling through it. The higher the R-Value, the better the thermal performance of the insulation. R-values are split into zones based on your location in the country. Avoid adding insulation over any heat sources, as this poses a fire risk. Also, grab a buddy to help speed up the process.

Difficulty: 3/5; Only looks like it took all day

Time to complete: 4 to 6 hours, depending on the amount of insulation and prep needed

What you’ll need:

Tools

  • Tape measurer

  • Meter ruler or yardstick

  • Blowing machine

  • Vacuum

Supplies:

  • Insulation

  • Tarp

  • Work or latex gloves

  • Mask

  • Extension cord (if no nearby outlets)

  • Safety goggles

  • Metal or other fire-safe barrier materials

  • Kneeboard

1. Create Barrier Around Fixtures

First, you’ll need to ensure fixtures are covered to avoid a fire hazard. Barries come in the form of metal, wood, or IC-rated luminaries. Create barriers over fixtures such as:

  • Recessed light fixtures

  • Chimneys

  • Furnace flues

  • Heating vents

  • The attic door

You’ll need to create a barrier of at least three inches, but check your local codes to see exactly how high your barriers should be.

2. Load Up the Blowing Machine

Grab your gloves, masks, and safety goggles for this next step. Also, enlist the help of your project partner. Load up the blowing machine with the cellulose, breaking up any clumps in the insulation as you go to prevent clogs in the hose. Lay a tarp underneath the loading area to catch any of the loose insulation, because if the insulation picks up on debris, it becomes unusable.

Your partner will need to continuously feed the insulation into the blowing machine, so keep an open line of communication during the process.

3. Turn on the Blowing Machine and Spray

Turn on the blowing machine, and in unison with your partner, work the machine hose to spray the insulation into the wall cavities. The insulation should stick inside and create a compact seal without any extra work on your end. When spraying cellulose insulation remember:

  • Start in the corners of the room to ensure you don’t end up cornering yourself

  • Spray the floors of the attic if insulating the area

  • Do not fill the floors any higher than the joists

When the floors are finished, turn off the machine.

4. Level Out the Insulation

cellulose insulation in wall
Photo: helivideo / Adobe Stock

Once you spray your insulation, it will cover the joists and studs on the wall and floor. Next, you’ll need to remove the excess insulation and create a smooth surface for finishing applications. Grab your meter stick (or anything wide enough to expand across two studs) and run the meter stick down the wall, exposing the studs but keeping the cellulose insulation in the wall cavities. This will drop all excess insulation to the floor, which you’ll take care of in step five.

The same process applies to the floor joists if you’re working in the attic. To ensure you don’t fall through the ceiling, level out an area for the kneeboard. It’ll also be easier to level out the rest of the floor this way.

5. Vacuum Any Remaining Insulation

Suck up any remaining insulation with your vacuum. Head on over to your local waste management website or give them a ring to determine where to dispose of the material properly. Insulation can not be thrown into a normal garbage can.

Should You Hire a Pro for Insulation Blowing?

Out of all the different types of insulation, cellulose insulation is DIY-friendly, but insulating your home is still an intermediate-level project.

If you’re not comfortable handling the blowing machine, are unsure of the fixtures you need to cover, or can’t find a helping hand, then consider leaving this job to an insulation company near you. The average cost of labor for insulation installation is around $0.25 to $0.50 per square foot. Your pro will take over measuring the square footage, buying the proper insulation to reach your optimal R-value, and installing it correctly.

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