I had a lot of cedar decking boards I took off my old raised beds (they were a seat all around the bed) to put the boards to good use, I thought my daughter in law would like a box to attract owls, but no, she wanted a bat house!
After searching the web I decided to take the advice from the Bat Conservation International www.batcon.org and see what they had to say about successful bat houses, then I had to modify things a little, just to make it “mine”.
I made a video showing the jigs I used with my bandsaw and the modified plane blade to make the required grooves for the bats to climb on, Youtube video here: https://www.youtube.com/watch?v=UE_PN5fBVtI
After cutting the notches and the grooves in the long boards I glued (Titebond III) all the joints building layer by layer when I completed each layer I, pocket screwed on the inside both ends of each board, big saving on time with clamping the glued joints! One thing about cedar, being quite soft, there is NO need to clamp the pocket screw jig when drilling, I know this sounds crazy, but try it, it just works! Check this really short video https://www.youtube.com/watch?v=hIEz1fS0W38
Okay when pocket screwing hardwood, clamps on the blue jig are with out a doubt Needed.
To groove the inside boards and each side of all six baffles would have take a lot of noisy saw time so I chose to modify an old Victory plane blade. With a grinding stone in my Dremel I carefully ground 3/16” deep grooves to marks I scribed in the black paint I had put on first. This blade I then honed just like a regular blade with my honing guide.
Then the battens were secured and the baffles slid into each slot and fixed with screws.
One coat of yacht oil finish on the outside (Seafin) I dyed the deco bats with red Rit dye and coated them with Seafin
-- Love thy neighbour as thyself