I had to cut down my very old Elm tree about 8 years ago. It was over 100' tall and approx 14' in diameter. It had survived the dutch elm disease of the 60's. It was a sad day! My question: When the root system of a tree that large breaks down, will it affect the structure of a house that was build on top of it? I'm sure that the root system for this tree spread for blocks. My house has been here for 50 years (me for 30 of them, I am noticing cracks that weren't there before and watching the stump break down over the years made me wonder if underground they go soft and could make the house shift and settle.