How to Bat Proof Your House

The memory is burned into my mind; My husband and I were lying in bed at about 11:00 PM when we began hearing a scratching sound in the floorboards above us. At first I was ready to ignore the sound, hoping it was the house "settling," but soon I could not deny that there was something crawling around in the floor of the attic. My husband bravely went upstairs to see what he could find. When he went upstairs, the sound immediately stopped, but after he came back to our room and we were quiet for a few more minutes, the sound resumed. I hoped that we were only hearing a mouse, but I knew that what we were probably facing was a bat problem.

The next day my fears were confirmed when my mom bravely took a tour through our attic and discovered "bat droppings." She said that she didn't think we had them very bad, but that they were definitely up there. I was completely overwhelmed at the idea that there were bats flying around our house at night and immediately got to work seeing what we had to do to get rid of them. Because our budget was very tight at the time, calling in a professional was not an option. Here is what I learned and how my husband and I got rid of them:

1. Find out where they are coming in. Bats enter dwellings such as houses, barns or abandoned buildings at daybreak to sleep until the dusk to come. They generally hang upside-down while they roost, but they are also known to squeeze into cracks in floor boards or ceilings, or even hang behind pictures or curtains. Until you find where they are entering your house, you may not be able to get rid of them. Bats usually find a place to roost at the beginning of the year (late May) and continue there until migration (September), even giving birth to one or two babies in their seasonal "home." And yes, they will return to the same roosting place every spring.

In order to find out where they are entering, you may need to take a trip to your roof. Check around your chimney, vents, and shingles for small openings through which a bat could squeeze (they only need an opening 1/4" wide). If you do not find the entry point this way, check carefully around attic windows and screens, or turn off all of the lights in the attic and see if you can see any outdoor light coming in.

If the above methods don't work, you may need to stand watch outside of your house at dusk when the bats go out to feed. When the sun goes down, watch your roof and upper windows for bats leaving.

2. Seal the entry points. Once you know where the bats are coming and going, you need to seal up the holes. However, if you seal these areas during the daytime, you will be trapping them inside your house. If you want to avoid bats coming downstairs in order to find a way out, you will need to seal the openings at night time, after the bats have left. This method is not fool-proof however, since bats do not necessarily leave their roosting place every night. Certain weather conditions and other factors could make them stay. In this case, make a one-way door so that the bat may leave your house without being able to re-enter. For example, if you find the entry point is a window screen, affix a wire, 4-sided "box" to the outside of the window. The bats will drop immediately once they get outside of their opening, but they will not be able to fly back up the box to get back inside. After at least two days of allowing the bats a one-way exit, seal up all openings with new screen, trim, spray foam insulation, shingles or concrete--whatever you need.

3. If you see them, kill them. I know, this sounds harsh. However, bats are very territorial. Just because you seal them out of your house does not mean they will not look for a new way to get in. They will probably look for a new entry point for several days after you seal up. If you find them in your house before you have sealed the entry points, after you let them outside they will immediately go back to their roosting place (probably in your attic). Killing them is the only way to keep them from re-entering until you are 100% positive your vulnerable areas are taken care of.

Our bat saga lasted about two weeks. In that time we had one bat flying around our living room one morning, found two roosting over the oven and a window, and also had one flying around our house in the middle of the night. Though it was a stressful time, by following the previous suggestions we were able to take care of the problem ourselves with very little cost.