I have built a pair of bat houses using these plans at Bat Conservation International.
A finished house weighs about 25 lbs (11 kg) and I would like to attach it to the outside of my house, over horizontal 3/4" cedar plank siding.
Here's what I have in mind.
I made some wedge mounting plates that fit into the natural slope of the siding and provide a flat surface.
I plan to attach the plates to the siding (liberally caulked) with 4" construction screws and then attach two horizontal "french" cleats (upper and lower) on which the bat house will rest. The top and bottom halves of each cleat will be secured to each other at the exposed ends with a metal bracket so the bat house cannot be lifted off the cleats in strong winds.
My question: Will the siding tolerate this load if the plates are screwed into the siding?
Based on recent work replacing gable siding, I expect there's a gap between the siding and the OSB sheathing, so reaching a framing stud is unlikely, and I'm not sure I would want to put a screw through the Tyvek anyway.
Also, assuming this will work, is there anything else I need to be aware of?