Blown-in insulation
Blown-in insulation is loose-fill fiberglass or cellulose blown through a hose into an even, deep layer, and it is the most cost-effective way to reach R-49 or more in an attic. We install it in new-home attics after drywall and top up existing attics across Isanti and the north metro.
Both work well when they are installed to the right depth. Loose-fill fiberglass is light, doesn't absorb moisture and settles very little. Cellulose is made from recycled paper treated with a borate fire retardant; it is denser, slows air movement better than fiberglass, and is the material we use to dense-pack existing walls.
We'll recommend one based on your attic, your budget and what is already up there.
Minnesota's energy code calls for R-49 in the ceilings of new homes. Depending on the product, that takes roughly 14 to 20 inches of loose-fill. We install to the manufacturer's coverage chart, which lists both the depth and the number of bags per square foot, so the R-value is real and not just a guess at the depth.
The energy code also requires depth markers in blown attics, at least one for every 300 square feet, facing the attic access. They let you and your building inspector confirm the depth at a glance.
The edges of the attic are where most blown-in jobs go wrong. Insulation blown into the soffits blocks the intake vents and starves the attic of airflow. Before we blow, we install rafter baffles that hold open at least an inch of air space above the insulation, plus wind wash dams at the top plate so the insulation can go full depth right to the outside wall.
Blown-in insulation fits most attics, old and new:
FAQ
Most attics are done in a few hours to a day, depending on size, access and how much air sealing and baffle work comes first.
Cellulose settles somewhat after installation and fiberglass very little. The manufacturer's coverage chart accounts for settling, which is why we install to the chart's depth and bag count rather than just eyeballing it.
Usually, yes, as long as the existing insulation is dry and clean. If it is wet, moldy, smoke-damaged or contaminated by rodents, it should be removed first.
Keep exploring
Baffles, soffit-to-ridge airflow and full-depth insulation to stop ice dams.
Learn more about Attic Insulation & VentingOld, wet, rodent- or smoke-damaged insulation vacuumed out and hauled away.
Learn more about Insulation RemovalFlash-and-batt and targeted air sealing to hit Minnesota's 3 ACH50 blower door target.
Learn more about Air Sealing & Hybrid Systems
Building a barndo, a custom home or a shop? Reach out and we'll set up a time to see it. No pressure, no guesswork pricing.
