Im going to build a block chimney on the side of my house the question i have is what kind of a footer do i need or do i need one at all? The block will be sitting on my driveway concrete and i will tie the chimney into the house of course with straps. should i bust up concrete and pour a footer? i live in northwest pa it gets cold here also chimney will probably be around 20 feet tall.Is there any write ups on people building theses thanks in advance.