Blown-In Insulation in Beaverton, OR

Blown-in insulation is loose fiberglass or cellulose fed through a hose by a blowing machine. On an attic floor it settles into every bay, around wiring and blocking, and over the tops of joists, forming a continuous blanket. In closed walls it can be packed tight through small holes. For most Beaverton homes, it is the most cost-effective way to add a lot of insulation.

Fiberglass or cellulose

Both work well; the differences are practical.

• Blown fiberglass: about R-2.2 to R-2.9 per inch, with little or no settling. It does not absorb much water and is naturally noncombustible. It takes more depth to reach the same R-value.
• Cellulose: recycled paper treated with fire retardant, about R-3.1 to R-3.8 per inch. It is denser, slows air movement a bit more, and settles roughly 10% after installation, so it is blown a little deeper to allow for that.

HomeGuide lists installed costs at about $1.00 to $2.80 per square foot for fiberglass and $1.20 to $2.80 for cellulose.

Blown-in for attics

On the attic floor we blow to a set depth rather than a set number of bags, and we staple depth rulers to the framing so the level is visible. The goal for most local attics is R-49 or more, which the Oregon code requires in new flat ceilings and which the Department of Energy suggests for existing attics in our climate zone that already have a few inches. Before blowing, we air seal, install baffles at the eaves, and build a dam around the hatch so material does not spill out each time it is opened.

Dense-pack for existing walls

Many Beaverton homes built before the late 1970s, and some later ones, have exterior walls with little or no insulation. Rather than tear off drywall, walls can be filled from the outside or inside: we remove a strip of siding or drill small holes in each stud bay, insert a tube, and pack cellulose or fiberglass tightly enough that it will not settle. HomeGuide puts dense-pack cellulose at about $1.60 to $4.20 per square foot. The holes are plugged and patched; when we work from inside, painting the patches is usually a separate step, and we spell that out on the quote.

Things we check before blowing

• Recessed lights: only fixtures rated for insulation contact can be covered
• Chimneys and flues: clearance dams around heat sources
• Knob-and-tube wiring: in older homes, it should be evaluated by an electrician before insulating around it
• Bath fans: ducted to the outside, not into the attic
• Moisture: roof leaks or stains are fixed first
• Vermiculite: if present, we do not disturb it

How blown-in fits with incentives

Attic and wall insulation have both been eligible under Energy Trust of Oregon's insulation offers for customers of participating utilities, subject to the program's existing-R-value and installed-level rules at the time. We list existing and installed values on your quote; confirm current terms with Energy Trust.

Keeping it tidy

The blowing machine stays outside or in the driveway and the hose runs to the attic hatch, so there is little traffic through the house. We lay drop cloths along the path, protect the area under the hatch, and vacuum up when we finish.