Howdy.......I'd try a rasp rough it up a little bit......What type of
wood were you planning on using......dig the rasp in a bit but don't
push it the whole way across and it should give the little critter
plenty of stuff to grab onto...

Here's a link for some bat house plans........

http://www.batcon.org/bhra/economyhouse.html

Sorry I'm not fluent enought to make it a link.............



Anybody have suggestions for getting bats to move out of my house and
into a bat house? I have an older (circa 1890) home and the bats just
love it in the awnings.......