Coop: varethane the interior?

[oliolio]

New to chicken coops. My design is to use 2 cabinets I've found, back to back with ramps leading into the partially open backs, separated by a 15' covered run.
Question is: how do I prepare the cabinets? They were found pretty rough and I'm wondering if I need to seal the inside, like, do I do layers of varethane inside and use caulking in the corner seams? Is that overboard? Thought it might make cleaning easier and be more sterile of an environment for the girls.

Also I was thinking of leaving the exterior unfinished. These cabinets were found outdoors. I figure if they're covered with a roof it shouldn't be a problem. Thoughts?
So excited to find you all!

 

[Urban Flock]

That is mostly up to you. A wide flexible topic. Coops are made out of just about anything and painted or unpainted. We used an old playhouse that had plywood inside and T-11 on the outside. I painted the outside with red and white barn paint. The inside walls were painted white so left them as is. Floor had linoleum on it that we removed and left the wood. I keep a layer of pine shavings in there and clean the poop often. We looked at several coops on line and drove around checking out what was in the area. So what we finally settled on is that you can make it as simple or elaborate as you want. We did a lot of research before we started and that made the final design easy. There are a lot of things to consider. Nest box sizes, ventilation, lighting, roost size and heights and the more you research the more you come up with. You will eventually land on something you like as far as the surface finish and design. I wouldn't recommend caulking because the ventilation thing is really important. You don't want an air tight coop. So the caulking may be a bit overboard. Welcome to backyard chickens and good luck with your project.