I got a call from my insurance company today. Apparently they didnt know I had heat in my garage. I think they are going to want to inspect it. I know it is not up to code. It is a Lennox oil burner. There is no attic space so the chimney goes right out the roof. Is it to code to run single wall pipe and only run double wall insulated two feet under and above the roof? If so, is there an adapter to hook the single to double. Thanks