Simple Bat House

Cut the two 1x10 back boards to 16-1/2" and join them edge-to-edge with pocket screws and glue to form the full back panel.

Cut shallow, parallel grooves — about 1/8" deep — across the interior face of the back panel, spaced every inch or so. This is the surface the bats will actually grip and climb, and it's the one detail that determines whether the house gets used at all.

Cut the two 1x3 side boards to 20" and attach them flush to the back panel's edges with glue and screws.

Attach the 1x10 lower front board and the 1x6 upper front board, leaving a deliberate 1/4" gap between them — that gap is the bat house's ventilation, not a construction error.

Cut and center the 1x6 top board (19-1/2") flush to the back, securing with glue and screws.

Sand all edges smooth. Leave unfinished or use only a non-toxic exterior treatment — skip paint and stain entirely.

Mount high on a wall or tree in a spot that gets morning sun; bats favor roosts that warm up early.