Hot Topics: Can Attic Insulation Deter Rats?

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Unfortunately, there is no rat-proof insulation. However, there are options for keeping rats out of your attic and attic insulation. Take a look at some of the advice provided by these DIYers.

Original Post: What Type of Insulation Helps Deter Rats?

ceiling Member

What type of insulation is a rat's least favorite insulation? I know that no insulation is 100% rat proof, but surely different types of insulation keep them out more or less.

Highlights from the Thread

PJmax Group Moderator

Roxul would be the least rodent friendly... except maybe for cellulose.

XSleeper Member

Mice love all types of insulation equally. I don't know that spray foam was tested in the study below, since it was not popular when this test was done, but I would imagine it would be similar to polystyrene.

IMO spray foam would be your best bet, but poison bait stations should probably be used in the attic to help control the number of unwanted house guests.

Bud9051 Member

Any air-permeable insulation will allow them to detect what is on the other side and then they will go right through it. I've seen plywood where I suspect there was a small gap that provided the motivation for them to design their own door.

Your defensive steps should start on the outside with traps and bait (if allowed) before they get inside. Then, I like to have traps where I can see them easily to know when they have located a new entrance. Rats are rare here, but mice are everywhere, and they will keep looking until they find a weak spot.

Wherever you are looking to install the rat-proof insulation, it needs to be either enclosed on all six sides, air tight, or have a wire screen covering that they cannot get through.

Tony P. Member

While cellulose insulation is less mouse/rat-friendly than other insulation choices, I don't believe it will "deter rats." But, even if it did, what does that really mean? If, for example, you put insulation in your attic that is not rat friendly, I can't imagine the rats leaving your building; they would just go elsewhere. After all, rats don't go into your building because of the insulation.

Eliminating rats is a 3 pronged approach:

  • Stop entry,
  • Eliminate food sources,
  • Kill what remains.

If you have enough rats to consider insulation options (and 1 is too many), entry is no longer an issue, and I suggest focusing on killing first. Make it a multi-pronged attack with more than one poison and a variety of traps. There are techniques for maximizing trap success and I'd look into those.

Finally, are you talking about crawl space?

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