How do I put foundation under one wall of my home that sits on the gro

Bless you. Just try to remember what he did and improvise as you go. The problem is soil on wood, so dig under the bottom log and place a barrier. You could hire young people to dig a new trench for a cement foundation.

Old log cabins often used big flat rocks or bricks as a foundation. You want to keep the wood from rotting and getting termites. If you absolutely have to do this job alone, then do it bit by bit.

Do all of this from the outside of the cabin wall. DO NOT get under the floor or wall.

Start at the higher corner of the dropping wall. Dig a hole the depth of the rock, cement block, or three or four bricks you will use for homemade piers. Place your Pier, then tap or hammer it under the corner. Use a bar level at that end. If it is not level, use a rock or metal wedge to bring it up to level.

Next go to the center of the wall. You know you need a higher Pier than the first one. Dig an approximate hole then measure up to the level bottom of the room. Place your Pier, then measure the level, and adjust by wedging. Then go back between these two and place another Pier to add stability.

Next, go halfway between the center Pier and the lower corner. Place, wedge and level the fourth pier.

You have not had to jack up anything so far, and you should be able to do the last Pier the same way. This Pier will be the tallest, so be very careful about your safety. It's better to dig a little deeper and use a couple of rock wedges than to try to level a very tight Pier.

I don't know why Pier is capitalized, but it makes it easier to keep up with five Piers. Best wishes 😇