Help with odd basement (LONG)
Hello all. New guy here in a real pickle. Would like to have some advice on framing/finishing a messed up basement. Long story short (this is really messed up), our contractor built our basement a foot too wide. Nobody caught it until weeks later when half of our modular was sitting on it. The set up crew split the difference (in width), and now the front and back of my house are sitting on the foundation walls by only the outer rim joist. The modular company are having us frame up 2x6 walls inside to help support the house, and we're unsure what we are going to do with the 5" ledge on the outside. I know. It's insane. We are trying to push forward though...
Any advice is appreciated on this whole situation, but the reason I am posting right now is to figure out how to--under the circumstances--properly frame and finish the basement. We are in Mineral Co. WV, I believe climate zone 5. The walls are 8" poured concrete with dimple board on the outside. Back side is 3/4+ below grade, front is above grade, sides slope down accordingly. I have searched and read for hours about this and would like to do the XPS against the walls and then also fill the cavities with something else. The problem is, I don't want to move my framing out more than a half inch or my header won't be under the inner rim joist.
Right now I have about 24' of framing complete, and don't want to go any further until I figure this out. We were holding out 1/2" from the wall, and using PT bottom plate. Also I sealed the interior walls with Foundation Armor S2000, and now (after all of my reading) I'm not sure that was the right thing to do. No way to change that now though.
Could I use 1/2" XPS and make up the difference in the cavities?
Thanks for any help/advice.