Project: outside remodeling; replacing old deck with a screened in porch and smaller adjacent deck, all at the same level as the main floor of the house; there is a basement that opens to the backyard, under the old deck; outside this door is a regular concrete slab ("CS #1"). When the old deck is removed, the space above CS #1 will be open and CS #1 will become the floor of a new room at the basement level. On the main level, in the space adjacent to CS #1, will be the new smaller deck and the back porch, which will open to a sunroom that previous owners had added to the back of the house. The new deck and the back porch will, like the old deck, form an L around one end of the sunroom. At the top of the L, on the same floor as the sunroom, is a kitchen. At issue is the "L-shaped" space under the new deck and the back porch, adjacent to the house wall and CS #1 formed by the vertical part of the L. In this adjacent space is a large "slab" of concrete ("CS #2"): it abuts CS #1, but rises about 18 inches higher than CS #1; you cannot tell how deep it goes into the ground. On the side of CS #2 away from the house, there is a ramp so that you could roll a lawn mower up to the top of the slab. I want this slab removed to give more headroom to the space, making it more useable for storage and gardening activities. The contractor does not want to remove it because "we don't know what it is or why it is there". (The house was built in 1964, so we are unlikely to find out when and why the slab was put there.) Has anyone else come across something like or very similar to this? Any ideas as to what it is or what purpose it serves, or originally served?