Building my first wooden vivarium for my corn snakes

[Alexa02]

I posted this previously in the enclosure section but I'll reupload here since I have cornsnakes.

So I'll be making my first wooden Vivarium soon, I have plans drawn out. It'll be like a shelving unit almost, two separate cages for my two male corn snakes. Storage under and it'll reach about 5 and a half feet tall, I want it eye level not touching the ceiling. I have a few questions I'd like to ask anyone who can help me.

Like heating, it'll be wood, and I see some people still use heatpad and it seems to penetrate through the wood and not cause any problems, with corn snakes, I feel like I could use light fixtures and heating bulbs, but being as this is my first Vivarium build I'm not completely sure on what's best. Best to heat the ground for belly heat and safety for my snakes. This is probably my biggest concern for my build. My snakes do like to burrow so I'm just torn between the two.

I live in Chicago, recently it has been storming, humidity goes way high, 70 to 80 and higher. Even in my house, it still stays around 60 maybe 50 if it's a good day. Any help with lowering the humidity? I will be getting a dehumidifier for my room, but With a wood Vivarium I'm a little curious on the ventilation. I see cup size holes and they seem to think it's enough, I see others with house hold vents screwed in the side. Having cornsnakes I hear it's best around 30 humidity. Up to 50 but shouldn't go higher cause they couldget sick. I even had a little scare where I saw dry or damaged scales, maybe 3 on one of my snakes. But no darkening on his underbelly, so I don't think it's scale rot. I still am bathing him in diluted iodine and washing him off and drying him. Just to be sure till his next shed. So humidity is a problem for me and any suggestions would be great.

I think those are my main worries at this time, building the actual shelving and glass windows aren't a big deal. I have the help of my uncle who is a construction worker. All the tools and such are ready. He even suggested melamine, it's already fairly water proof, he thinks it'll work great.