Attic Insulation in Beaverton, OR

Attic insulation is where most Beaverton homes gain the most comfort for the least money. A typical house from the 1970s or 1980s started with a modest layer of fiberglass or cellulose on the attic floor, and decades of settling, storage, cable runs and the occasional rodent have left it thinner and patchier than it looks from the hatch. Adding insulation is simple in concept, but the order of the work decides whether it actually performs.

Why air sealing comes first

Insulation slows heat moving through it; it does very little to stop air moving through it. In a Beaverton winter, warm indoor air rises and pushes through every gap in the ceiling: the top plates of interior walls, holes drilled for wiring and plumbing, gaps around the chimney and flue, the attic hatch and older recessed lights. That air carries heat and moisture into the attic. We seal those openings with foam, caulk or sheet material before any new insulation goes down, because once a foot of loose-fill covers them they are very hard to reach.

Keeping the attic ventilated

Most attics around here are vented through the soffits and out at the ridge or roof vents. When insulation is blown all the way to the eaves, it can plug the soffit vents and stop that airflow, which leads to damp sheathing and, in our climate, mold on the underside of the roof. We install baffles at each rafter bay so air keeps moving from the soffits up under the roof deck, even with deep insulation on the floor. We also check that bathroom and kitchen fans are ducted to the outside rather than dumping humid air into the attic.

How much insulation to add

The current Oregon Residential Specialty Code calls for R-49 in flat ceilings in new construction. For existing homes in our marine climate zone, the Department of Energy suggests R-49 when there are already 3 to 4 inches of insulation and R-60 when the attic is bare. With blown-in fiberglass, which runs about R-2.2 to R-2.9 per inch, R-49 means roughly 17 to 22 inches of depth; cellulose, at about R-3.1 to R-3.8 per inch, gets there with less. We put the target R-value and depth on your quote and leave depth markers in the attic so you can check them.

Blown-in, batts or spray foam

• Blown-in fiberglass or cellulose: the usual choice for open attic floors; fills around framing and wiring without gaps
• Batts: practical where the joists are clear and evenly spaced, or for knee walls in finished attic spaces
• Spray foam: for sealing and insulating tight spots, vaulted ceilings with shallow rafters or attics being turned into conditioned space

Most Beaverton attics end up with air sealing plus blown-in insulation. Spray foam has its place, but on an open attic floor it usually costs more for the same R-value.

When the old insulation has to come out

Clean, dry insulation can stay in place under the new layer. It should come out if it is wet from a roof leak, soiled by rodents, moldy, or in the way of air sealing that cannot otherwise be reached. If we find vermiculite, a pebbly gray-brown or silver-gold loose-fill, we stop: the EPA says to assume it contains asbestos and not disturb it, and removal is a job for a licensed asbestos abatement contractor.

Energy Trust of Oregon

Attic insulation has been one of the measures covered by Energy Trust of Oregon incentives for customers of participating utilities, typically with a cap on how much insulation is there now and a minimum level to install. Terms change, so check Energy Trust's current offers. Your quote lists the existing and installed R-values so you have the numbers the program asks for.