This is the final, dry-assembled, unglued, unpainted, version of one of the doors.
The rest of the doors is a matter of temperature control, primer and paint, and then installation.
Installation is going to be … OK, I think. I was a bit worried about that, but there’s a big steel header beam right over the door on the inside of the building, so that means I will need to construct a wooden header beam for the outside and connect it to the one inside, through the wall, which is thinnish steel. That’s going to be a matter of buying a couple sheets of pressure treated or marine plywood (probably marine) and ripping them up, gluing and screwing, priming and painting, then positioning, levelling, and bolting and screwing. Once I have a plan for how something is to be done, and I know it’s going to work, the whole project feels easier.
After this is done, I have 6 more doors to make, for the other side of the room. Those will be narrower but have similar dimensions, to echo the big doors visually. They will run in a track made of a piece of 3/4″ polypropylene silicone caulked and screwed into the concrete. The bottom of the door will also be a piece of polypropylene; it should glide beautifully and, since water will pool/run up against it, the poly will simply not care at all. Instead of making those doors out of 2x4s I will use pieces of 3/4″ plywood laid up on either side of a center-piece of 1/2″ plywood, which will hold a bottom panel that’s a stressed component of the door to keep it stiff. I’m using plywood because it’s more dimensionally stable than 2x4s and if the construction is 2x4s it’s necessary to layer and lap them so they are basically plywood. I want the side doors to be movable, which means not making them as heavy.
This is what is in my head: