darkened insulation

General Inspection Topics General Inspection Discussion
1

I was asked about this by a contractor, sorry no pictures.

Does anyone have any ideas why this would occur on a 4 year old townhome?

The attic insulation looks normal on top and good down 6 inches with typical pink blown in insulation. The lower 6 inches or so is much darker with shades of brown and dark gray.

Also the baseboards have some of this darker insulation oozing out along the edges. Nothing looked unusual in the hvac filters.

Original owner and no past history of leaks or mold or anything unusual.

2

Is there a whole house fan?

3

Could be the installer used one color insulation until he ran out and finished with another. Could be the additional insulation was added later.

I did a commercial office building one time that was completed in 4 stages and had 4 different insulation in the attic areas. (I guess whatever was cheapest at the time.)

4

What about Chinese drywall. Can that cause darkening of insulation like it does with copper?

5

I wouldn’t think so. This insulation is most likely made of fiberglass. Copper turns black because of it’s reaction to the sulfer dioxide in the drywall. Fiberglass doesn’t react this way.

It could be mold though growing on the dirt and dust that is on the fiberglass.

Without seeing it first hand, my money is still on the “different batch” of fiberglass though…

6

What I have seen most often in the past was from air movement inside the wall/ceiling.

Insulation is designed to slow or stop air movement.

In the process, it acts like a filter and removes particulate matter from the air as it passes through the insulated space.

I find this discolored insulation when I am “investigation further”, IR anomalies I have identified.

You find it at the baseboard because this is where the air first enters the walls due to “stack effect”.

7

Fiberglass insulation does have some magnetic properties. When it gets dusty enough, the insulation will turn grey, as will mold. Jury is sill out if the sheet rock causes the insulation to turn other colors. I have seen it here on rare occasions mostly due to dust collection.

8

If the “Fiberglass” is in fact Glass (though other materials are also used), there will be no effect on the glass from these chemicals.

“magnetic properties”; did you really mean “magnetic” or “magnetic like” properties?

Magnetism is how materials respond to an applied magnetic field.

All materials are influenced by the presence of a magnetic field but they do not always have that attraction to other substances as in the case of paramagnetism.

I have a GEMS unit that measures magnetic orientation and intensity of materials (used for subsurface geological assessment) so I’m interested in anything you have about this.