We have a root cellar that is about 100 Sq ft with a height of about 8-9 ft. Our backyard backs up to a wooded area and our root cellar is located at the very back part of the yard, built into the hill/drop-off into that wooded area. This root cellar was built years ago, we moved in 1.5 years ago and have noticed the cellar is in horrendous condition. Looks like that part of the backyard could fall through as the ceiling simply seems to be held up by railroad ties laid across the ground above. The railroad ties are all rotting away. My question is what would be the best course of action to ensure this area is safe? What should it be filled with? Can we reasonably do this ourselves?