I had a builder put up a raised 10x13 post and beam foundation in anticipation of a shed placement later. I measure it and find the diagonals are 4" off. What is the easiest way to adjust the rhombus back to square? Do I add a shim piece to the 6x6 posts on opposite corners?
*Edit: Attaching another image to show exagerated shape and diagnals. Also the 2x8 attached to the posts with lag bolts