Long-term mouse infestation in unfinished basement. I want to remove&replace poop/pee-filled ceiling

Factual Questions
1

The ceiling in our unfinished basement has pink fibre insulation between the joists. Thanks to a couple now-plugged holes, lots of mice have made the basement their home for a decade or so. The existing insulation is holding up an enormous amount of faeces and dried urine, and we’d like to pull it down and replace it with new insulation (sans the crapfest).

My plan (after I stop screaming like a squeamish six-year-old), is to get a painter’s suit, tie it snugly around my wrists, put on nitrile gloves, a dust mask and safety goggles and yank the existing insulation down into a heavy-duty garbage bag. I’ll probably start screaming like a squeamish five-year-old at that point. Then take a spray bottle of diluted bleach, dampen the exposed joists/floorboards, let it dry, push in the new insulation, and then, finally, stop screaming like a squeamish 45-year-old. Oh, and shower.

Contact-wise, is the painter’s suit/nitrile glove barrier sufficient, or are mice cooties (of the actual, dangerous kind) likely to make it through? I’m assuming that in the process a lot of detritus will come falling down upon me (hence the repeated screaming).

The safety goggles I have are basic splash resistant. Or do I need something more robust?

And lastly, right now all I have are basic dust masks. That can’t be good enough—what would I look for? A full-on respirator?

While it’s one thing to purchase a handful of equipment, we’re not really in the position to hire someone to do the entire basement at once (between re-insulating and overall square footage it’s quite a bit), so we’re hoping to do this small section by small section over time.

Oh, if it makes a difference, our location is rural New York and these are field/country mice.

Thanks. I’ll be over in the corner whimpering.

2

I guess I’d use a standard dust respirator (the kinds with little round filter packs and pre-filters, not the cheesy paper face masks). Aside from that, you precautions seem reasonable. I don’t think NY is a hotbed of hantavirus,but it doesn’t hurt to be cautious.

I had roughly the same issue when I remodeled – aside from the decades of mouse poop, you should be prepared for the occasional mummified rodent. Because nature is a beautiful thing…

3

I agree, a decent respirator will be far better. Get one that fits well and has large filter cartridges, not the nickel-dimey ones on the bottom shelf at Home Depot. Keeping that dust and particulates out of your lungs is well worth $20-25.

Some kind of a bag frame will help, too. I’d use the really big yard bags and one of those folding frames that hold them open for leaves.

Nasty job. Nasty critters.

I’d try to do the pull out all at once - get the old crap (lit.) out of there, do the first round of cleanup, then do the full cleaning and replacement/repair in whatever steps make sense time and money wise.

4

I went through the same thing, only rats in a finished garage attic. Great fun.

As Finagle says, hantavirus is the main concern with rodents, but shouldn’t be a problem in your area. See here for CDC guidance. Nitrile gloves should be fine. I’d also be tempted to use a dust respirator, not just a mask.

I don’t like the bleach idea. Urine has ammonia, and as you know, bleach and ammonia don’t mix. I kind of doubt there’s enough ammonia to cause serious problems, but I wouldn’t put it to the test. This site recommends using an enzymatic cleaner first.

Be sure you’ve taken care of the infestation too. They’ll just move back in to their nice clean home if you don’t eradicate them.

5

Well, it’s not a *hotbed *of hantavirus, but there have been a few cases in the last couple of years, so I’d get more than a paper dust mask.

6

I’m going back on my earlier statement and agreeing with GrumpyBunny. The cases of hantavirus that make the news seem to be more in the southwest, but its extent certainly can include rural NY. Get a decent respirator.

7

Second using enzymatic, urine-neutralizing cleaners. Try to find them in bulk - much cheaper than pint bottles at PetCo etc.

8

I’ll strongly recommend having a largish Shop Vac with a fresh filter to make to make all the little crap (literally) disappear before you start spraying liquids.

9

Gently clean up as much as you can with a broom first. Even with a new filter, the vacuum will stir up a lot of dust and it’s best to minimize that. The respirator will hopefully take care of the rest.

Ideally you’d use a low-power vacuum or not use one at all, but having done it myself, it just isn’t feasible to clean it out of all the cracks and crevices without a strong one.

10

When I was removing some serious asbestos and other construction debris, I was able to rent a HEPA vac from my local Tool Rental Center for something like $40 including bags. I own two shop vacs but this thing was amazing with capturing every iota of dust without losing any suction. Even dry wall dust was gone! So on top of a good face mask, rent a real vacuum with great filters and you won’t have to worry about blowing it around your house for years to come!

11

Look for a head sock in the spray painting section of your local lumber store. $25 seems cheap to keep mouse poop out of your mouth, although I think the fiberglass dust would cut your lungs to shreds before you’d get any disease from the droppings.

This is kinda cheezy, but when you’re done with all the removal, set up some fans on the windward side of the basement blowing in, some fans on the leeward side blowing out and crank up a leaf blower. Get all the dust and poop airborn and let the air currents carry it all off. You did say rural …

Your local ASPCA should have many many house cats available for good homes, get a half dozen and that should end the problems.

12

This sounds almost as bad as an episode of Hoarders I saw.

13

I’m exhausted. Just move.

14

I think you should wear something sturdier than nitrile gloves when you’re doing the actual pulling down because nitrile gloves tear so easily. Get a pair of thick rubber gardening gloves and wear them over the nitrile ones. When you’re finished with the pulling down stage, just remove them.

15

CDC site, “Cleaning up after rodents”

My initial impression after reading your OP was “yeah…don’t know about just a hardware store dust mask.”

Half-mask air purifying respirator with a HEPA filter sounds about right to me. I work at a large chemical company so these are standard issue for R&D people like me. A quick google search says such a respirator might be $20-$30, cartridges also maybe $20-$30.

For a nasty job like that - I’d say wear one. Costs a lot more than a simple dust mask, but it would be a one time cost. No reason to skimp. Safety first.

16

I say stick with the bleach, or a bleach based cleaner. The amount of ammonia wouldn’t concern me too much with regards to mixing with chlorine (although you do want a good fan blowing in fresh air NOT just circulating) and nothing kills like bleach. It’s what we use in the lab.

I’d be doubtful of the effectiveness of the enzymatic cleaners ability to kill viruses and spore formers. Also, if damp enough there is a good chance of mold spores, which will also succumb to the bleach.

This is not a job for a weak cleaning agent.

17

A site I referenced above recommended enzymatic cleaner first, then bleach. I agree you want the strong stuff at some point, but it’s best to start with the enzymes to clean up the uric acid. This site says it’s the only way to deal with it (although I can’t vouch for its accuracy).

18

Having done a lot of nasty, messy, uncomfortable jobs in my time I have great sympathy for the misery ahead of you.

I just wanted to add that not only will a proper respirator be more effective than a paper dust mask, but it will be way more comfortable and likely to stay on your face. Every time I issue a crew dusk masks at work they are all off after 20 minutes because they are so bloody uncomfortable. Paper dusk masks just do not have enough airflow, they are essentially useless because nobody will leave them on. The painters sock sounds like a great addition.

19

Okay, here’s the new plan. First, I contact SpaceX and inquire about getting me into orbit…

If that doesn’t work out, the next thing is to get one of those bag frame things. I have no idea what they’re actually called, but they’d be damn useful in wrapping up the insulation.

Next is a strong pair of disposable gloves to put over the nitrile gloves (I forgot how easily those tear).

Then I’ll get a ‘real’ respirator. I’m seeing a lot of different standards out there (lead, mould, asbestos). Is there a minimum that I should meet?

I may even upgrade my safety goggles—who the hell wants mouse pee-soaked insulation fiber in their eye?

And forget the painter’s suit. For about the same price (under ten bucks), I can get a Tyvek suit with built-in elastics. Sure, overkill, but MOUSE POOP!

Cleaner is an interesting question. The main recipient of said mouse poop is the insulation, which isn’t being saved. (For the moment I’m turning a blind eye to all the mouse poop that has collected on the miscellaneous junk we have down in the basement.) That means when the insulation is pulled down, I’ll just have exposed joists and flooring above. There’s minimal (if any human-detectable) small, so I’m primarily concerned with what could happen X years down the road when I move the insulation around again for whatever reason. Since it’s summer (and since the need to insulate basement ceilings seems to be somewhat debatable), I can do this in two steps. Take it all down now, leave everything exposed for a month or so to dry out/die, then hit it with a bleach spray. Leave it soaked in for another week (yay procrastination), and finally put new insulation up there.

Or are there nasties that enzymatic cleaners will take care of that bleach won’t? The linked article seems to say that uric acid will persist long after drying. But if I’m not concerned about the smell, does it matter? If there’s a few weeks exposure to the air (it’s dry down there because we run a dehumidifier), will the ammonia likely evaporate enough to alleviate the risk?
Dammit, I hope SpaceX comes back with a reasonable estimate. There is a lot of insulation down there and even doing it one section at a time will take several weekends (and dollars) to finish the whole thing.

20

Fill a spray bottle with enzymatic cleaner, or splurge for a $10 pump sprayer. You can spray down all the joists and flooring in half an hour or less. Do the same with a dilute bleach solution after a few days. You might not notice the smell now, but do you really want to realize it still lingers when the house is shut up through the winter? It’s trivially easy to do it now; it will be a pain in the ass later.