Blown Cellulose Insulation: To DIY or not to DIY?

It’s the end of January, and winter has finally arrived in the Northeast. Cold snaps like these often prompt homeowners to upgrade their insulation.

At Sealed, we’re big fans of blown cellulose insulation for attics and walls. It’s cost-effective and gets the job done far better than fiberglass, particularly when it comes to keeping your home warm and reducing your heating bills.

At first, blowing cellulose insulation into your attic may seem like the perfect DIY project. It sounds simple: go into your attic with a hose and blow insulation until it stands 15 inches tall. What’s so hard about that?

It turns out that properly insulating an attic requires a couple challenging steps before blowing the cellulose. You might think twice before doing them yourself.

Air seal before you insulate

It’s critical to seal your attic’s air leaks before installing cellulose insulation. By sealing the leaks in your attic, you will double the energy and comfort impact of blown cellulose.

The average home in the Northeast is 2-3 times as leaky as it should be, and the majority of leaks are found in the attic. At Sealed, we routinely find leaks along top plates, around recessed lights, and in areas where wires and pipes enter the attic.

Air sealing is unfortunately painstaking and time-consuming work. We typically install half a mile of foam when sealing an attic, requiring 10-12 man-hours spent on hands and knees in a cramped, uncomfortable space.

In case you’re wondering, it’s also a bad idea to blow insulation and then go back to air seal. Air sealing is difficult enough without needing to dig through 15 inches of cellulose.


Install baffles before you insulate

First, what the heck is a baffle?

Baffles prevent moisture accumulation in an attic by making sure that air is circulating properly.

The baffle does a few key things:
• Keeps the soffit vent clear of insulation, allowing air to flow freely
• Allows you to insulate as close to the vent as possible without obstructing it
• Directs air away from the insulation, preventing it from blowing around like confetti

Installing baffles incorrectly or neglecting to install them can lead to a serious mold problem in your attic. Minor mistakes by an amateur can cause major headaches and home health issues down the road.

The Verdict

While blowing cellulose in an attic isn’t terribly complicated, it needs to be done in combination with proper air sealing and correctly installed baffles. It’s better to get the whole attic done professionally than to install only blown cellulose by yourself.

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