I'm 99% positive that they were not "wolmanized", yet they were never  showing any signs of rot, even on the silage side   Thanks

Doors were made out of various species of wood, such as Douglas fir, spruce, hemlock, cedar... 

  Our silo doors were 28W x 24H x 1.5" thick. They consist of 2 layers of 3/4"

t&g, one layer horizontal and the other vertical and were nailed & clinched.  The doors had and offset on the top and bottom to lock into the door below.  Each door has a metal hanger to hook onto the rebar that went across the door way.  The doors set in a 1 1/2" deep x 2" wide recess on each side of the doorway.   When opening the silo, we would hook one or two doors on the top edge of the silo, which would give two or four feet of open space to the chute... 2 foot opening wasn't enough for the Badger unloader, it needed 4' or would have a buildup of silage at bottom of door

 When filling the silo, it was easier to move the doors down just one space instead of two, but then had to put second door somewhere when using the unloader, which was to hang it on the unloader, thus it was the norm to hang two doors at the top. 

Lars, your correct, poured silo, 16x40.  It was built by a green crew with old used and abused forms that were so bad that dad was pounding them back into some formaty of a form... and then bucketing the concrete up instead of pumping it...  and was a wet season so they would pour two or three forms high and dad stopped at 40 feet when he would have gone to 60 if they would have known what they were doing.  What was worse was they put dry Portland on the joint when starting a new pour and it would leak water into the silo when ever it rained.  That was back in 1962.

  In 1965 the folks put up a 20x60 Harvestore that was taken down in 1966 because it was a silo from hell... because of so many problems incurred in the building of it. It had just three doors, two doors on top, one in the center for filling and one for the discharge of air. Then the one door for the unloader at the bottom.

 Have seen pictures of a few Harvestores that were converted to doors up the side to use conventional silo unloaders.

FDG, some of the fancy silos had a swing in door so there was no 'extra' door to move or hoist.

I haven't climbed a silo in quite a few years but always enjoyed working on the harvest crew in my teens and early 20's.  Thinking about it, I can't think of one upright silo in the entire county that is still being used.  A guy a few miles away has a couple harvestors on his place, they are covered with cell antennas, I head he makes close to $5,000 a month on them, a lot more then he ever made squeezing teets.

Trust me, our doors did NOT swing in  !!