I just got done digging most of the patio out that im doing in pavers. It was an old patio with about 12in of cement. I rented a jack hammer and had almost all of it done but by the door. Under the door entrance was the normal 4in sidewalk and under that near the foundation is about another 13inches of cement. I really dont want to get to close to the foundation. Its about 6 in from final grade i was wondering if would be alright just to go over the top of it with my base stone.