Rodent contaminated insulation

Specific Inspection Topics Ancillary Inspection Services
1

This seemed to be the best forum for this question since there isn’t one on insulation/ventilation.

Over the past couple years, we’ve had a handful of callbacks from people that had pest control companies come in, tell them their insulation is highly contaminated from rodent activity, then give them a long report with a five figure quote to remove, clean up, then replace all attic insulation. Prior to a couple years ago, this was unheard of, at least in my area.

I know we do not inspect for mice on a regular home inspection, and I will bring up this as well as the fact we generally don’t disturb insulation at all, but this smells like a racket to me, especially seeing the price tags. Air generally flows out from the house to the attic, not the other way around, so I cannot see how contamination level of the insulation matters to the house occupants, unless they are in an out of the attic moving things around all the time.

The only effect I see from the mouse activity is the tunneling and matting will lose some R value, but heavy contamination is usually only seen in older houses that have low insulation levels where improvements are being recommended anyway.

Anyone else have experience with this? Does anyone look for and report this? The only times we report is when there are visible, substantial piles of feces on top of the insulation, but we do not move insulation to check what’s below. What are your thoughts on insulation contamination in general?

2

If I find excessively contaminated insulation, basement or attic I recommend replacement. A few droppings I tell them mice activity. Insulation that is heavily stained (dripping with urine in some basements) should be replaced.

3

I reported it and the amount and condition the owner Makes the decision on how to handle the situation .

Some clean it them selves other’s get a pro and some do nothing .

4

Heavy infestation can have wall insulation affected as well, there is also a possibility of electrical wiring being damaged in areas that are not visable.

5

If I knew that there was no active infestation, and I also knew there were only a few droppings or patches of urine, I would not be particularly concerned, but I can rarely see the entire attic, so I err on the side of caution. An active infestation can lead to serious health consequences, so the buyer/owner should be made aware of the situation.

I was once in a house where the infestation was so bad you could smell it in the living space. Can’t imagine how that would be anything but unhealthy.