My house is in a very rural location. Next closest house is probably 1000 feet away. Across the street are acres and acres of hay and vegetable fields. Have always had a mouse problem when I’ve lived here, but now doing contract work out of state. Cat helped the mice somewhat, but we really have had a lot.
Frankly, the mice seem to have mostly moved out now that there are no people living here and sharing what food they could get into. I haven’t heard them when returning occasionally.
But I have one room on the south side of the house that the mice have routinely nested in for years, and I can smell them. Not everyone can, but I can, and want the wall torn apart and rebuilt. I might be doing AirBnb and trying to reduce any contamination.
The downstairs interior walls are quirky in that they are not sheetrock, but panels of wide pine, and they are insulated between the two interior board walls… I’m okaying tearing out the wide pine boards that face this room, and replacing them with sheetrock. Another issue is that I beieve the one wall they are mostly in serves as a chase for plumbing from the upstairs master bath, and then down into the crawlspace plumbing.
So after they tear these boards out, and replace with sheetrock, any recommendation about what they should line these interior walls with?
Don’t want to hear the lecture about plugging up every hole. House is cedar sided on the outside. They will find a way in out here. It’s wide open country.
But just wonder if there’s anything that would work better than others to keep them out of those interior walls.
I also haven’t poisoned the mice in the past. Didn’t want kitty-cat to be affected, and we have hawks in abundance here that I don’t care to poison.
Thanks for your suggestions!
Can’t say without seeing how your framing is there, but when we built our tack room, we ran a bead of steel wool along the places a mouse may find to get in, like on the top of walls and around any wire or pipe intrusion on the blocking.
The blown in insulation they used is supposed to deter mice, don’t know if that is really so and if you have that kind there.
We have not had any mice in there … yet, anyway.
Surely whoever you have doing that remodeling work will have some ideas of what works where you are?
We have a company come out quarterly and spray the perimeter with a deterrent. It’s all natural, smells piney, I guess? A few mice still come in, but the snap traps placed inside (attic, garage, basement) grab them pretty quickly. Nothing has the chance to move in.
I use Terad3 in the barn, though, for the rats. It’s a non anticoagulant poison and there is no/nearly no risk of secondary poisoning with it. It’s even recommended by one of the Audubons. The pest guys recommended it when I had zero luck trapping the rats. They were just too smart. Before I put it out, I spent a lot of time googling and couldn’t find a single mention of any secondary poisoning cases in any species. Put it out in locked bait boxes. Might be an option for you.
I opened up a couple walls in a house I used to own and one thing I found was that each heat register had a mouse nest on top. (The house had hot air heat with registers in exterior walls about a foot or 2 up from the floor.) Smart mice - very comfortable quarters, extra heat and comfy nesting material (the insulation) - but I didn’t want them there! I wasn’t going to do what was necessary to exclude the mice from the unfinished basement so I needed to block them from entering the walls. (The cats already kept them out of the living quarters.)
I realized that though the heat ducts coming up into the wall were round, the openings cut in the bottom of the wall cavity were square. That provided 4 approximate triangles that were large enough for a mouse to come up. The only stud bays with evidence of mouse presence were the ones with the heat ducts, so as far as I could tell that space around the ducts was the only entry point.
I could have put steel wool in the gaps, but instead cut tin (opened-up cans, in fact) to fit tightly around the heat ducts and close up those holes, screwing it in place so it wouldn’t shift.
I just re-insulated with regular fiberglass insulation, since I didn’t think mice would be getting in there again.
Your mention of the plumbing chase made me remember this - you may be right that the plumbing provides the route for the mice to access the wall.
any recommendation about what they should line these interior walls with?
rather than fiberglass insulation I would use mineral wool product such as Rockwool, There is nothing scientific to back this up but
There is no test method to determine whether or not any product is rodent resistant. ROCKWOOL’s reputation as a rodent-resistant insulation is mainly based on word of mouth and lack of negative feedback from numerous customers who use our products in “cottage country”. That being said, if a certain pest type is a nuisance to your particular area, best practice is to protect the insulation.
Mineral wool, which is also commonly called rock wool, comes in easy-to-install batts, similar to fiberglass. But instead of being composed of fluffy glass fibers, rock wool is made from volcanic rock, primarily basalt.
also since you specifically stated the plumbing chase
- What happens if ROCKWOOL insulation gets wet?
ROCKWOOL insulation is moisture resistant yet vapor permeable. In the event the insulation becomes damp or wet, the insulation, when thoroughly dried, will maintain the original performance characteristics.
ROCKWOOL stone wool insulation does not wick water, which means that any bulk water that contacts the outer surface will drain and not be absorbed into the body of the insulation.
Thank you, everyone. Gives me a few ideas.
Now to see if my handyman has any time in the near future!
Best bet is a flash and batt combo. A half-inch of closed-cell sprayfoam (seals everything) and then rockwool to fill the cavity. A regular “handyman” type will not be able to apply the spray foam, though.
OP, if you’re replacing insulation in upstate NY, check out NYSERDA for incentives, etc. to help offset costs.
I recommend spray foam as well. We have spray foamed all of our outer barn walls and floor, ceiling and walls in our tack room. There’s no way a mouse could get in there and boy, is our barn warm now!
We studded all of our stone walls (bank barn over 200 years old), had a company come in and spray foam all inbetween the studs and then drywalled the tack room celing and used tounge and groove for the walls. Our barn we used plywood overtop for in the stalls and pine tounge and groove for the aisles.
It was more money in the end, but totally worth it!
What is the long term behavior of spray foam? We opened up one wall edge and it had “shrunk” and dried out.
It was the corner of our sun room, two sides had exterior exposure (versus an interior wall).
Properly applied closed-cell spray foam should not shrink or sag over time if properly protected from UV. It is used a lot on the exterior of flat and domed roofs, especially in the south (like the Superdome in New Orleans post Katrina) and in those applications it is protected by a UV reflective coating.
Open-cell foam is not as rigid, so may shrink over time. It is also much softer and moisture permeable.
Most closed-cell spray foams are about R 7/inch, and open-cell foams are in the area of R 3.5/inch.
The spray foam they use here is a thin layer, maybe 1"?
I don’t think that would have much to shrink.
We have it in our metal shell well house, has been there over a decade and a half and is still like new.
It is toasty in there in the coldest weather.
foam, I have had problems with rats chewing through
Our barn has foam in the walls and feed room has fiberglass batts, either has provided any deterrent to rodents … plugging holes with steel wool that is not removable has stopped them
I used Rockwool – what Clanter suggested – 6 inch batts + 2x6 wall studs for superior heat retention in winter. My contractor maticulously sealed every possible crack along sill plates, window/door framing etc. with liquid nails – any gap that mice could widen/chew through. Room is sealed like a drum. Hoping for the best – that mice will choose a path of least resistance like under hay pallets or elsewhere to make nests and not in my tack toom walls.
Spray foam was way to expensive – fiberglass was a cheap not so good option – Rockwool was middle of the road expense so I opted for that.
