Hi,

I’m redoing a 1905 house in NW Ohio. The 8×20 porch on each side has sunk about 1″ over the last hundred years. My guess is over the last 30-40 where the gutters were not ever fixed and water poured with every storm.

Assuming I’m going to redo some rotted joistwork, and replace the porch floor, add gutters and fix the drainage, my question concerns a good fix, given the damage you see and how long it has taken. I understand frost heave, but in this case, it was water washout causing a drop. 

There are 3 courses of block above ground, and 1 below, and finally below that what appears to be solid blocks about 16″ wide. I included a drawing.

My intention is to remove all the cinder blocks around the corners (they are loose anyway) and then pour some concrete a few inches wider on both sides of the slab blocks, plus a layer on top of the slab, maybe throwing in a steel mesh, to roughly equal the amount of sag over the years. This is versus digging a 36″ish deep tube and filling with concrete.

Does anyone think this should be sufficient, or should I go the harder route?