7 Tips We Learned While Adding Blown-In Insulation to Our Attic

My husband and I recently unlocked a new level of marriage: We survived insulating our attic together! I guess you could say we had a third wheel, since we used the AttiCat machine to fill our attic with fiberglass blown-in insulation.

This project is a win for everyone. Eric loves that it lowers our energy bills, and I love that it lowers our carbon footprint in service of the birds, bees and other animal friends.

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DIY Blown-In Insulation Tips

Here are the seven things we learned while insulating our attic.

1. Prep the Space Beforehand (Got Two Months?)

When people say that blowing in insulation is easy to DIY, they are glossing over all the prep work that comes first. Eric was in the attic almost every day for two months getting everything ready.

Air Sealing

Eric added foam boards around our attic walls and floor, air sealing for energy efficiency. Even if you don’t want to air seal, you’ll still need to spray foam around light fixtures, pipes and other holes, so the insulation won’t drift into other parts of your house.

Air sealing attic with rigid foam board and spray foam

Some types of light fixtures need to be protected with a “dam” so they won’t touch the insulation you add. Other fixtures that are IC-rated can touch insulation.

We also added irrigation flags to mark our fixtures so we’ll be able to find them again in the future.

Helpful Air Sealing Tools

Eric says the spray foam gun is a big improvement over just using the can. The gun is reusable for up to 30 days and has a stiff tip that is easier to control for reaching tough spots in the attic.

Vent Baffles

Next, it’s vital to protect your home’s ventilation holes. You’ll need to staple baffles between your rafters so that the blown-in insulation won’t clog the vent holes. That way, air will still be able to pass through the baffles above the insulation, to promote air flow and prevent mold.

Baffles protecting attic ventilation holes from blown-in insulation
Here are our baffles holding back 15 inches of insulation.

We also found out that we didn’t have enough ventilation holes to begin with, so Eric spent several days cutting holes in the side of our house, adding screens and then installing the baffles.

Baffle Materials


Our attic didn’t have any kind of walkway, which makes it difficult to maneuver without putting your feet through the ceiling, Clark Griswold-style. So Eric also built this walkway and insulated underneath it before the big day when we finally blew in the rest of the insulation.

Building attic walkway before blowing in insulation

2. Use All the Safety Gear (and Maybe More)

Don’t let the hard-to-see fiberglass dust get you. Even though this insulation is considered a low-dust alternative to the itchy insulation of the past, some particles will get in the air during this DIY project.

Eric was the one in the attic blowing the insulation. This requires safety goggles, gloves and a mask. Eric upgraded to coveralls and a full-face ventilator, and as you’ll probably guess from the video, he was glad he did!

Eric blowing insulation into attic with hose

Meanwhile, I was in the basement inserting the insulation into the machine, which also requires safety goggles, gloves and a mask. Since the room looked dust-free, I thought my eyeglasses would be good enough, but after a couple of bags I was coughing and my eyes were scratchy.

Also, I removed my mask when the machine was off, not realizing the dust that I couldn’t see was still very much in the air. I wish I would have worn full safety gear whenever I was in the room with the machine.

Safety Gear

3. Get Assistance From Your Bungee Cords

The AttiCat insulation blower has a 100-foot hose that loves to flail around when all the insulation is blowing through. Enter: bungee cords.

We used bungees to help hold the hose in place around our staircase railing and in the attic entryway, so it wouldn’t fall down into our hallway and start spraying insulation all over the house. Very helpful!

Eric also used bungee cords to attach a broomstick to the end of the hose, which made it easier to reach nooks and crannies in the attic.

4. Don’t Overstuff the Machine (Oops)

Another mistake on my part! I thought my job was to keep the insulation blower absolutely stuffed at all times to keep things moving. But it’s kind of the opposite of that.

Since the insulation expands so much when it releases from the bag, if you over-stuff the machine it can make it hard for the insulation to break up and move into the hose.

Inserting half-bags of expanding insulation into AttiCat blower machine...it takes oomph!

The official AttiCat instructional video actually says to wait until you can see the paddles in the bottom of the machine before adding another half-bag of insulation. This makes it so much easier to add insulation and avoid jams.

I also found it helpful to have a staging table to pre-cut the bags and slide them into the machine.

If it seems like the bags aren’t wanting to open up, make sure they are catching the built-in cutter inside the machine. The whole process takes a healthy amount of oomph!

Here’s a closer look at the handy quick-start guide on the AttiCat.

AttiCat quick start guide showing how to insert insulation into blower machine

How Many Bags Do You Need? That depends on how thick you want your insulation. We opted for R-44 insulation, which is about 15 inches thick and considered more than enough for our area. Use this volume calculator on the product page to find out how many bags you’ll need for your space. And keep in mind, if you buy 10 bags, you can get the machine rental for free at Home Depot.

5. Brace Yourself for an Explosion of Cotton Candy

There’s no low or medium setting. The machine is either off, or in fire hose mode. The pressure was so strong that when Eric aimed the hose directly where he wanted the insulation, sometimes it would blow too far past the goal.

So he learned some tricks. He used his gloved hand to guide and slow down the insulation, and sometimes he aimed at the ceiling so the insulation could gently fall into place. Again, he was happy that he opted to wear coveralls!

Eric suggests aiming the hose parallel with the bays. If your attic doesn’t have a walkway, plan your route and start at the farthest point, so you don’t have to walk back over the insulation to get out.

Eric's legs sticking out of attic with AttiCat hose and chunks of insulation on the hallway floor
Insulation cascaded into our hallway below the attic door.

Have everything you need ready before you turn on the machine. We set up string lights and had extra bungees and an extension cord nearby for easy access.

Whatever you do, don’t drop anything! Our broomstick is now buried somewhere in our insulation, never to be seen again.

Also, the AttiCat comes with a remote control so the person in the attic can turn it off if needed. When we rented the machine, the sales associate said the remote control had full batteries and was ready to go. It was not. You might want to have them test it in the store before you leave.

Helpful Gear

  • Caged utility lights (I dubbed them ugly string lights, but they were very helpful!)
  • Portable work light
  • Insulation rulers to gauge the depth of your insulation (typically available for free at Home Depot and anywhere AttiCats are rented)

6. Use a Concrete Mixer for Touch-Ups

After you take the AttiCat rental back to the store, you might still have spots in your attic that you need to fill in later on.

When we blew in the insulation, we kept it out of the area where we wanted to eventually install a fan. So after the fan went in, Eric used a concrete mixer to break up additional insulation and insulate around the fan.

Of course, this method isn’t nearly as efficient as the machine, and it doesn’t break up the insulation quite as nicely, but it works in a pinch!

Air sealed attic with fiberglass insulation

Most of the insulation in this photo was blown-in, but near the walkway you might be able to spot some of the chunky insulation we broke up with the concrete mixer.

7. Clean Up With a Shop-Vac in Reverse

When you’re all done blowing in insulation, your attic might be pretty messy like ours was. Some of the insulation had blown into our baffles, blocking the ventilation holes, which is not good.

Eric used a makeshift rake to level out the insulation and help clear it off the walkway. The rake was okay, but our Shop-Vac — in the magical reverse setting — was indispensable.

Eric went outside the house and put the vacuum hose against all the ventilation holes to shoot the insulation out of the baffles and back into the bays of the attic. Then he used the vacuum to blow insulation off the ceiling and walkway in the attic, making everything nice and tidy.

Happy Customers

Here’s the end result. We achieved R-44 insulation, which is about 15 inches deep. The house has been noticeably warmer, and we’re looking forward to watching our energy bills go down!

Attic after DIY air sealing and blown-in insulation project

Blown-in insulation, 7 DIY lessons learned when we insulated our attic
Blown-in insulation, 7 DIY tips we learned

4 thoughts on “7 Tips We Learned While Adding Blown-In Insulation to Our Attic”

  1. That was a major, major task/project you guys took on. Attention to all the details to do it right..Amazing!! Great job and big accomplishment!! Now you can reap the benefits of a job well done! Go Eric and Tara!! ( I also enjoyed the video which shows the effort and detail that went into this of doing a job the right way!)

    • Thanks, Judy! This project just kept going and going. But then actually blowing in the insulation only took about 2 hours. It is nice to have it all done and start enjoying a nice, warm house!

  2. Wow Tara, that’s great. Spending any amount of time in the attic doing insulation is zero fun. After Hurricane Ian, I had to get up in the rafters to remove a bunch of wet insulation, fix a bunch of wet ceiling sheetrock, and install fresh stuff. At least I was installing rolled insulation, so I didn’t have to do as much prep work as you and Eric. Speaking of putting a leg thru, did I send you a pic of the result of me doing a Clark Griswald impression? It was just too bad no one was in the living room to witness it.

    • Haha, you did send me that pic! Wish I could have been there! Yeah, attic work is tough with the low ceiling attics and no floor. It’s nice to have it all done. 🙂


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