Posted on March 11, 2007
Tags: housing

This is a bit of a saga, so I’ll do a quick intro before I get to the guts of it. I purchased a house in December 2006, and after a month or so living there I noticed a scratching noise in the walls. I pulled out the air-con, and looked into the wall cavity, and there was a roosting bat. So I did a bit of research into them, and decided they were getting in around the air-con, so I left the air-con out one night, and late in the evening sealed up the hole, and put it back in. Of course the next night there was still scratching, but not only there, in the ceiling as well.

The main issues I have with them is the smell of their droppings, and the rashes which we all get when we are at the end of the house they are in, so I assume there is something in the droppings which we are allergic to.

Pulling the roof off I discovered a large colony of bats living there, probably about 20 I guess. They were living everywhere, including under the ridge cap, and especially under the insulation bats. It turns out that the walls aren’t sealed in the ceiling, so the real path bats took to get into the wall was via the ceiling, and the exit appears to be via an unsealed ridge cap end.

So, I’ve tried a sonic deterant, but this doesn’t seem to effect them at all. The best information I’ve found so far seems to imply that the frequency it is using is outside the range which will effect bats. It does have a test mode which 1/2s the frequency, but this is quite loudly heard by the rest of us in the house, which is not really desirable.

What has seemed to be a way of controlling them is to remove the insulation bats, and placing fluorescent lights in the roof space. The bats just seem to crawl, not fly, so perhaps they are actually babies. This was suggested by the national parks people.

So the plan as it stands is to clear out a perimeter around where they are mainly congregating, done by removing insulation, cleaning, lighting, and placing naphthalene in the cleared space. Then I’m going to try to do a sweep of the rest of the roof to make sure there are no other signs of them around, followed by blocking up all the wall tops where there are no bats present, and then trying to contain those in the wall. I think I will give the infested wall cavity direct access to the outside world, probably by removing the air-con, and hopefully with time they will move on.

Then the cleanup operation can begin. I estimate I have a cubic meter of bat dropping to remove, probably by shovelling the industrial vacuums.

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