I bought a Oak Ridge fireplace insert and we are going to install it in our masonary fireplace. The outlet of the insert is 12" x 8.125" which is about 96 square inches. Our chimney is lined with tile that is 11" x 10.25" which is about 110 square inches, but it looks it's not lined all the way down. We are in South Carolina do we need to line our chimney? How can I make an adapter to connect the insert to chimney pipe?