Bat House Forum

[Skyhigh82]

I can only find Berch 4x4 post at a local home depot which I'll attach to a 4x4 treated post. Is Berch ok for the housing part?

[Joe Spencer]

Birch 4x4 post? I am confused, are you attaching two posts together as an extension to have one longer post? If the birch is on the top that is fine if you are intending to use spacers and have the 4x4 as part of the first and smallest interior chamber.

[Skyhigh82]

Yes because you can't use a treated post inside the house...correct?

[Joe Spencer]

I just use a PT post and slip the first box/core over the top eliminating the small roosting area with spacers on post which was part of the original design. Also the original design had the post notched on the upper area so if you go this route indeed it is best not to use P.T. Since they eliminated arsenic from P.T. lumber years ago it is not as harmful as it once was but we usually don't have it exposed to bats. I just personally find it easier to make the first box true 4"x4" inside dimension to easily slip over the 3 1/2" post and not using the original design. Also if you're not already doing it, butting your box sides as seen below results in a fast completely square box for every layer you make. For the first core I rip the 1" rough pine boards at 5" so when they're put together such as below they end up being 4"x4" inside diameter as mentioned above. The box below is a larger layer: