Hello! I’m a first-time homeowner and I am trying to figure out how to find a door that does not have standard measurements. I have a storage shed attached to my townhouse and the door is rotting away. Here are pictures of it opened and closed. The door slab itself is approximately 27 inches by 80 inches but I think that’s too small because it won’t stay closed. It seems like 28 inches would be a better fit. As I said, the door is rotting away (place was built in 1984) and I would like to replace it with a sturdy exterior door. My front door is steel and that would be ideal but I don’t know if that’s possible (would it be too heavy for a storage shed?) Is this something I would need to have custom made?