I have built a pair of bat houses using these plans at Bat Conservation International.

Bat House

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.

Mounting Plate

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?

  • 1
    Find the frame under the siding panels and fix through to that.
    – Solar Mike
    Commented Oct 16, 2020 at 18:32
  • What's the best way to do that? Commented Oct 16, 2020 at 18:36
  • Look for nail/screw heads in a line. If there's a gap between the siding and the OSB, there's framing or furring making that gap, and that's what the siding boards are fixed to. You want to hit that.
    – Ecnerwal
    Commented Oct 16, 2020 at 18:53

2 Answers 2


Nice work with those mounting brackets you made. I think your basic plan is totally sound.

Ideally you'll want to locate studs and mount those brackets on studs, and drill through the siding and sheathing and into the studs. I think three 4" x 1/4" lag screws on each bracket would be good, there's enough meat to lag screws that size to hold the weight of the bathouse.

Rather than seal those brackets to the siding, I'd put a thick washer between the brackets and the siding. I'd rather have that little gap for the siding to get wet and dry out. That's just my opinion.

I see one possible problem with the design. The french cleat will leave space between the bathouse and the siding. The bats won't know which crevice you intended for them to take up residence, and roost between the siding and the bathouse. You might want to add to or modify your design to close off that space.

  • Good answer, but I'd give the bats more credit than that. They know when they're exposed to sunlight and wind and when they're not.
    – isherwood
    Commented Oct 18, 2020 at 17:45
  • @isherwood - where there's a lot of bats around, they love spots like that, the inch or so of space between the back of the bathouse and the siding would be prime bat real estate. Commented Oct 18, 2020 at 19:06
  • @batsplatsterson Thanks for the suggestions. After some misgivings and research I have decided that mounting a bat house to the side of my house is probably not a good idea, due to the potential mess. I will instead find a local organization that can accept a donation of the completed bat houses. Thanks. Commented Oct 22, 2020 at 0:35

If you're using 4" screws the plates won't be hanging on the siding. They'll be hanging on framing. Right?

No, you shouldn't hang anything on siding that you wouldn't want hanging on your nose. Use screws that penetrate at least 1" into the framing. Even screwing to siding + sheathing would be sketchy over time.

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