What R-Value Does a Portland Attic Need?
A quick, honest guide to attic insulation levels for our climate — and how to tell if yours falls short.
In the Portland metro, attics generally perform best between R-38 and R-60. If you can see your ceiling joists when you look across the attic, you’re almost certainly below R-30 and leaving comfort and money on the table.
How to check
Measure the depth of your existing insulation. Loose fill at roughly R-3 per inch means you’d want about 12–16+ inches to hit R-38–R-60. Thin, flattened, or patchy insulation is a sign it’s time for a top-up.
Why it matters here
Our long, damp, mild winters mean heat loss through the attic runs for months. Bringing an under-insulated attic up to spec is one of the highest-return upgrades you can make — and it’s often rebate-eligible.