Mouseproofing a Trailer

Tech > Mouseproofing a Trailer


Mice are famous for getting into trailers and chewing anything and everything they can get their teeth on - food, bedding, wood and wiring included. To insult to injury, they urinate and defecate. A LOT.

When we first started camping we heard that Bounce sheets and cloves would do the trick over the winter. And for the first couple of years, that seemed to work. Bear in mind that cloves look like giant mouse droppings, so prepare yourself mentally before opening your trailer in the spring. Unfortunately, one spring we learned they weren't much deterrent at all. See the following photo of cloves on a Bounce sheet - there's urine in the circle and the arrow points to droppings.

So much for Bounce sheets and cloves

We came to believe what many people before us have said - block EVERY hole a mouse could get in. And in a trailer, there are plenty.

You've probably come to realized that trailers are built in a big hurry, and the floor is no exception. It's likely to be drilled through in many places, for wiring, and water and propane pipes. And the holes are all the size of the biggest hole required, because that means the builders don't have to change tools. Here's an example.

Propane line - fridge

The best way to find these holes is to turn on the lights in the trailer, open all of the doors, and crawl underneath. Unless, of course, you trailer is covered underneath. Then you'll have to inspect inside carefully to be sure you spot them all.

All of these holes have to be filled. But how? One source said steel wool, because mice find it very unpleasant to chew. Makes sense. Another said brass wool, because steel wool rusts. That makes sense too. But just try to find brass wool! We found a good alternate, though - brass scouring pads. Like steel wool, the pads can be cut to the sizes you need, and poked in place with household items.

Ready to fill some gaps

Now, mice can push or pull brass wool out of holes, so after packing the hole with wool it's a good idea to block it in with something. We came across Pestblock, which is a low-volume expanding construction foam with a bitter agent that is distasteful to pets. I have read that Pestblock alone may not be enough, but with the brass wool it's a 1-2 punch.

Anyone who's used expanding foam knows that (1) it doesn't work well upside down and (2) the spray wand is not much use once the foam has dried inside and clogged it. We addressed both these concerns with several feet of 1/4" inner diameter clear vinyl hose. Now we could put the end of the hose in the hole while keeping the can upright, and should the hose clog, just replace it with another length.

Pestblock with 1/4" ID tubing*

The first step is to cut a bit of brass wool. It should be too big to fall straight through the hole, but not so large that it can't be packed in.

A little brass cut

Second step - pack it in!

Gap filled

Third step - back it up with some Pestblock. Go slow... it's sticky and can get everywhere.

Foam first, brass after (in this case)

But wait - there's more. Does your trailer have a pull-out power cord like this? This is commonly known as a mouse hole, and the power cord is like a highway for pests.

Mouse hole - open

If so, a conversion to a plug-in cord is a possible solution. We did just that with our first travel trailer... check out the write up at ParkPower RV Detachable Power Conversion Kit

Plugged in

These steps kept the mice out - for good.

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