Interested in designing a top bar hive from scratch? My Build a Top Bar Hive page describes the process.
But Mogans Jensen has illustrated and detailed the process in his more than 80 page free pdf Beekeeping with Apis cerana indica. It’s with a slightly different bee than our Apis mellifera. But the principles are the same.
Besides design, it’s a very good read for anyone interested in top bar hive beekeeping and sustainability.
I found this hidden gem while browsing bNews