Attic Air Sealing & Insulation in Green Bay, WI

Attic air sealing and insulation is the job that makes the biggest difference in most Green Bay houses. Warm air rises and pushes through every gap in the top-floor ceiling: around plumbing stacks, wiring holes, light boxes, the attic hatch and the tops of interior walls. In January that air melts the snow on the roof from below. The water runs down to the cold eaves, freezes and backs up under the shingles as an ice dam.

Why more insulation alone falls short

Loose fill and batts slow heat but let air through. Piling more fluff on an unsealed ceiling helps, but not as much as you would expect, because the warm air keeps moving through it. We seal the bypasses first with foam, caulk and rigid blocking, then add insulation on top.

How deep to go

The Insulation Institute's summary of Wisconsin's code lists R-49 for ceilings in Climate Zone 6, which includes Brown County. HomeGuide rates blown fiberglass at R-2.2 to R-2.9 per inch and cellulose at R-3.1 to R-3.8, so R-49 takes well over a foot of material. Many older attics around the city have 3 to 6 inches that has settled or been crushed during past work.

Ventilation and bath fans

A sealed, well-insulated attic still needs a path for outside air at the eaves and out at the ridge or roof vents. We install baffles so the new insulation does not block soffit vents, and we check that bath fans and dryer vents run outside instead of dumping moist air into the attic, where it frosts on the nails.