Have You Washed Your Attic Insulation Lately?

You best hop to it then if you haven’t!  If you do not keep your insulation washed you may be wasting valuable money in extra heating and cooling costs!

OK wait a minute.

Brain-fart.

This is silly—NOBODY washes insulation—what the heck am I talking about?

What I really mean is “wind-washing.”

I have not seen very many incidences of wind-washed insulation since I left the Great Lakes area—you know, where it always snows horizontally? Near the Great Lakes the wind can whip through bird-blocking and roof vents moving almost any insulation around a bit.

Today’s light weight insulation—especially the fluffy white fiberglass stuff moves around quite easily.

I don’t see much wind-washed insulation in attics in the Northwest.  Most of the wind-washed insulation I see is when someone has not connected the vent pipe to the fan and the fan blows the insulation all over the place.  At a recent inspection I found an example of wind-washing that I have not seen before.  It was caused by an unused roof vent termination for an exhaust fan.

Have you washed your attic insulation lately?

Of course it was an improper cap with no back-draft damper.  It was a regular screened roof vent that had been adapted for use as an exhaust fan termination.  Under normal use these screens plug with lint over time and there is no way to clean the screen rendering the exhaust fan ineffective. While I see these improper terminations quite often, I do not usually get a chance to photograph the screen inside because the ductwork is typically connected.

Screens plug with lint over time

But there is the screen—plain as day.

The vent was so low on the roof that the wind blowing through the vent into the attic had wind-washed the insulation exposing the corner of the ventilation fan.  The duct from this fan was terminated improperly at another similar roof vent—-as all the other vents in the home were.

Corner of ventilation is exposed

It almost looks like some critter took a nap there.

Exposing the metal casing to the cold temperatures of the attic can result in heat loss as well as condensation on the inside of the unit—resulting in rusting and damage to the unit.

The cap should be removed and the roof properly patched and proper caps with back-draft dampers should be installed on all the fans.  This was also new construction and someone should have known better at the time of installation.

Charles Buell

ASHI Certified Inspector Charles Buell has been the owner of Charles Buell Inspections, Inc. in Shoreline (Seattle), Washington, for over 8 years. He is a Washington State, Licensed Structural Pest Inspector. He was a licensed general contractor for more than 33 years. He is currently an adjunct professor at Bellingham Technical College, in Bellingham, Washington, in the Residential Home Inspection course.

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