I'm helping out a family friend with a mess they got themselves into. This house is in eastern Indiana, is quite old and has had significant termite damage. We had it treated 2 months ago and it appears that the infestation is over (for now), and I'm trying to get a handle on the repairs that need to be done. In some areas of perimeter foundation the sill plate can be swept out with your fingers and turns into dust. I have jacked up joists 2-3 at a time, removed the damaged sill plate and slid in new PT 2x8 lumber with sill plate foam under it and screwed the joists back into the new sill plate sections. In most of these areas I have also sistered the joists b/c of termite damage there as well.
Turning my attention to the inside of the crawl space (which is dry and fairly crawlable), I see a strange looking (to me) beam that is supporting the center of the house. I call it strange b/c it seems under sized and also is laying on its side. It appears to be a true 2x8 piece of old lumber, but it's laying with the 2" dimension perpendicular to the ground and the 8" dimension parallel to the ground. I have attached some pictures to this post. The center of the house that lies under this beam has sagged significantly. I can also see termite damage to a portion of this beam, but I'm struggling to figure out how to repair it. I don't even understand how (or if) it was structurally sound as it was originally built. The piers are roughly 2-3 feet apart (and not evenly spaced). Most are just stacks of cinder block that are somewhat buried into the soil, while some others are the same red terra-cotta blocks that the perimeter foundation was built with.
This house has a lot of history that I will probably never fully discover, but I would like to know if anyone has thoughts about this beam running down the center of the house. Is this common/expected/safe? And, of course, suggestions on how to safely and effectively repair/replace portions of it / all of it due to termite damage (or repair/replace all of it if necessary and if so with what)?