Your bat house should be built with either Cedar Wood or Exterior Plywood. When you build it you should aim to create a house that is at least 24 inches tall 13 inches wide and approximately 3 inches deep.
Your bat house interior should have either grooves at least every 1/4 inch or alternatively you can use a polethylene plastic mesh all the way up the front and back.
Build a Bat House
ow to Build a Bat House