A major part of what holds the roof up are four 20′ tall, steel columns made from 6″ x 12″ tube.  They are embedded 11′ into the basement concrete, and stick up 9′ in a vertical cantilever to hold the roof both up and firm.  The two that frame the front door can...

All that white stuff you’ve seen is ICF, or Insulating Concrete Forms.  This stuff is great.  It’s expanded polystyrene forms, connected with steel webbing.  You stack them like Lego(tm) blocks, with reinforcing steel, then pour in concrete.  The forms do NOT get removed, but...