This is a follow up to my previous question about blemishes on drywall.

Drilling a hole and sticking an endoscope up there showed mouse droppings and debris. It also showed basically open access to the entire floor / ceiling due to holes. I am now noticing similar blemishes elsewhere in the house.

What the heck do I do to move forward? I have called an exterminator, but even after all the mice are dead, I've still got walls of chewed up fiberglass, mouse droppings and urine.

Do I need to have all the drywall and insulation removed and replaced?

  • 1
    So - I guess you now know what your "fiberglass smell" really is ... sorry.
    – brhans
    Commented Mar 30, 2022 at 13:06
  • 1
    @brhans It is good to know, finally.
    – negacao
    Commented Mar 30, 2022 at 13:10
  • 1
    I don't know where you are in the world, but please be aware of hantavirus. Commented Mar 30, 2022 at 23:25
  • @JesseAnderson Yikes, good to know.
    – negacao
    Commented Mar 31, 2022 at 9:11

1 Answer 1


The droppings could probably be vacuumed up. The urine, however, will have soaked into the drywall and you just can't wash that stuff. Also, droppings may be embedded into the fiberglass insulation, and urine is likely to have soaked into the paper backing (assuming it's backed), and you're not going to be able to get it out of that, either.

You may be able to get away with patching small areas of drywall where the damage is obvious, but if the smell from the insulation is wide-spread, I believe your only option is to pull all the insulation out and replace it, which also means pulling down all the drywall in the affected areas.

Additional note: It's possible that some of the urine may have soaked into some less removable materials like joists, studs or top/bottom wall plates. While you've got sections of wall and ceiling open, look for stains on the wood and give anything suspicious a sniff test (yay!). If you do find stained wood, do a search and/or post another question about getting the smells out of the wood and take care of that as best you can before sealing that area back up.

In response to questions in the comments:

The nuclear option (replacing all drywall and insulation) would ensure that you got everything, however, your budget, patience, or SO might not tolerate that.

If it were me, I'd start by identifying where the critters are getting in and fixing that first. Then, and only then, would I start working on remediation of the interior issues.

Based on your series of questions, it appears that the smell is what's triggered this exploration and journey of discovery, so I'd start with the worst areas, replacing only what's most obviously offensive. Give it a week or two to air out (spring/summer, when you can open windows and run fans to get fresh air into the place would be ideal) and use your nose to determine if you've gotten the smells under control. Continue to replace insulation/drywall as necessary.

I wouldn't bother with taping/painting until you're comfortable that anything that's producing enough of a smell to bother you has been replaced. Just hang the raw drywall. Sure the house may not look pretty enough for a little black-tie soiree or a Country Living photo shoot during this time, but that's what it'll take.

Once you're satisfied that the smells have been eradicated, take a little breather (pun intended) and revel in your ability to conquer the critters, then set about all the finishing work.

  • From what I can see, the insulation is indeed torn up. My concern is that it's pretty clear the mice have widespread access to the entire house - as far as I can tell, all ceilings and walls are basically open to them. So I think at a minimum, I have to have the drywall and insulation replaced along the south wall, on both floors, and the drywall ceilings replaced.
    – negacao
    Commented Mar 30, 2022 at 14:17
  • Or do I need to go full nuclear, and have ALL of the drywall and insulation replaced throughout the house?
    – negacao
    Commented Mar 30, 2022 at 14:18
  • 1
    Thank you, @FreeMan. You more or less talked me off the ledge here. I have placed a ton of traps around the house, and poison on the exterior. I am waiting for the expert to look at the current mouse entrance and figure out how to deal with it.
    – negacao
    Commented Mar 30, 2022 at 15:24
  • 1
    I had a mouse infestation on the wall between the living room and the attached garage. I found out because the vermin had chewed thru a couple of circuits, electrocuting them. I tore all the drywall and insulation out. I found about 3-4 gallons of bird seed taken from a bag of it in the garage! The wall smelled awful. I sprayed the back side of the sheetrock (the living room side) and the studs with a bleach solution. Let it dry for a few days, then painted it all with KILZ, replaced the wiring an buttoned it up with new sheetrock. Commented Mar 30, 2022 at 15:30
  • 1
    Rodents can be infected with many diseases. Even in dried urin, hanta viruses were found. When removing the insulation, the air could be contaminated.
    – xeeka
    Commented Mar 30, 2022 at 16:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.