I was going to make 1, but I think I am just going to buy 1. Does this look like a good 1?

https://www.amazon.com/House%EF%BC%8CCarpenter-Pollinator-Waterproof-Handmade-Pollinating/dp/B09N6SRTFG/ref=mp_s_a_1_2_sspa?crid=3MRFN8WJ287XQ&dib=eyJ2IjoiMSJ9.9AchtCtvfoL-Kx2k-awFXMN3_E1yoYrZZWvq5ZWyohpj2MDKJLvzQIh_QZk2oQWpywsvXjJURATsOTy8wzIUOLks0R99i-z6FQS90cukMmpMRr0mPh_O6M_vUbSNWET3xJrff4fEz_JMqYsQlH2La_pOqQJqZug8ZLDfcoXAhsQGVDqPGZ1HPtTxbcOU-CeGh1V7bQlmxV_Y3VMKynH-4A.ctdEOrrxiyjOod_Jf_2L7_xnQ-QaWmYONKxHA6NM0No&dib_tag=se&keywords=bee+house&qid=1733455198&sprefix=bee+house%2Caps%2C302&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&psc=1

And when the Carpenter Bee's fill it up they can start in on your house!

I've never heard of carpenter bee problems in Wi, but I suppose it is possible

Why not just set up some hive boxes like beekeepers do?

It looks like a combo bee(not honey bee)/ butterfly hibernation box. Two important features a good bee house should have is hole/tube depth of 6” or more because mason bees lay a single egg in a series of approx 1” sealed cells with the first front four/five being all male(they are poligimous, males being more expendable to predation/disease). Not deep enough and you are not reproducing any female bees(not a good thing for future bees). Second is cleanable to prevent disease from continued use. Tubes need replacing each year. Holes cleaned and disinfected. Another positive feature is large predator protection screen at least 2” in front of house front. Like many things helping mason bees can get involving. Most important over housing is finding out if you have resident bees at your location as they have limited home range and are easily eliminated from habitats. They are also easily repopulated from other populations. Unfortunately most of the commercially marketed Bee houses are not designed for the bees but for bee house buyers. I have been helping native bees on our property for 30+ yrs and am still learning about them. Surprisingly in remolding our weekend cabin on our property generations of mason bees have been building cells underneath our vinyl siding we replaced. Mason bees are are highly productive pollinators.

I've never heard of anyone doing that.

Update: I bought 1. I'll probably put it by my fruit trees. I still have to decide how to mount it

You can cut bamboo or hollow reads bundle them and create the same habitat for them if anyone wants to try it. Makes great and cheap hands on projects for kids when doing pollinators class. I could not find any ol pictures on my phone to show.