Evening bats don’t roost in caves, but in trees that grow in their habitat, so it is important to use the right wood to build a bat house. It is best if the wood is stained a dark color, which holds in warmth and mimics the bark of the trees the bats like to hide beneath. It’s also important that the wood not be pressure treated, for the chemicals can harm the animals.
First, cut the wood to the right size, add grooves to the back and stain the inside. Then screw on the sides, the top, and the roof, and caulk them. This might take about six hours. Prime and paint the house, then mount it high up on a pole or under the eaves of a building. The house needs to be high up so the bats can have room to drop before they start to fly.