Don't know if this is the right place to post, but I'll start here...So I'm planning on moving a 100+ year old house. The floor joists are all in real good condition but are only full dimension 2x6's. The center of the house rests on a 6x6 beam running down the center. I plan on setting this down on a full basement but I want to have spans of at least 14 ft (house is 50x28). The 2x6's won't allow for this so it's looking like I will have to sister each joist with 2x10's. Not a problem. What I'm trying to figure out is when in the process of moving the house I should do it. You can't add 2x10's in after the house is sitting on the beams as these will be resting on the current 2x6 joists. Likewise you can't really do it after it is sitting on the new basement because notching the 2x10s to sit on the basement wall would be the same as sistering with a 2x6 (thanks for that info Tom Silva, ATOH).

The current foundation is brick crawlspace. I could notch out the brick, remove the rim joist, and slide the 2x10s in and sister them to the 2x6's. Then add a new rim joist. But I run into the problem of the having to notch the 6x6 beam that the house rests on. Another option perhaps would be to have the 8 inch basement walls to have a rim 4 inch wide by 4 in deep rim around the perimeter. The current 2x6's would sit on the top outside 4 inches of the basement wall rim and the 2x10's would be sistered and sit on the lower inside 4 inches of the basement wall. The 2x10's could either be notched yet would still be supported on the walls at the notched ends, or you could butt the 2x10 to the rim of the basement wall.

Anyways, I need some insight from you guys. I've asked an engineer buddy of mine but haven't back yet.