I have an existing 14 x 18 gable shed built on 8″ piers that is a couple of feet off the ground. I’m extending off the back with a shallow pitch shed roof that will overlap the existing 10/12 roof. The ground slopes down at the back of the shed, so I would like to lower the floor about 18″ below the current floor in order to keep head room at the outer wall, and have the floor closer to grade (will still be a little over a foot above the existing grade). If the floor was even with the existing structure, I would hang the new floor joists from the existing rim joist. In this case, the new lower floor level will be even with the piers. I’m wondering what my options are for supporting the floor at the existing shed without digging additional piers (the existing piers can handle the additional load the extension I’m building). Can I bolt a ledger to the side of 8″ piers? If so, the piers aren’t completely in alignment (4 piers on that side total), what would be the best way to shim without loosing strength? Can I hang something off the existing rim joist (like 3/4″ plywood), and attach my ledger to that and add a couple of lags to the piers to solidify it? Any other ideas? Any help would be greatly appreciated.