This design is a closed bottom. Thoughts on a SBB set-up? Or the need for one?
I have mine laid out with 3/4" ventilation holes in the top of the sides. I think a screened bottom would be too much, especially during chilly times. Being only two fames, there is not the mass of bees to keep things warm. I plug off the vents with wine corks when the weather is not continually hot out anyway.
I personally don't see the benefit of the added cost/effort of screened bottoms.