I would deeply appreciate any help !

I live in the north east and had a mason finish my outdoor fireplace . The first half was done by another mason including the firebox .

The fireplace is sitting on completely flat ground ,( note ) the property does have lots of ledge . I believe the foundation is only 4 inches . The fireplace is 5 feet wide by 7 feet tall .

My concern is the possible of having a problem with the foundation maybe not being thick enough !! I don't know anything about this , I only tried to hire the best people hoping they knew what they were doing ! We have spent so much money to date .

The second mason of course said he was not responsible if something happens .

What shouild I do , have a foundation built around the fireplace .

All responses would be much appreciated !

Thank You !