I'm building a new cabin with a Switzer boiler in the basement and a Jotul Oslo in the living room. My contractor arranged a mason to build the double flue chimney and hearth. The chimney goes through a cathedral ceiling living room and so is two stories high. I specified masonry/brick with stainless liners. My impression was that the chimney would be block, faced with brick above the basement, antique inside and new (antique appearance) above the roof. Now I find out that the mason has used block in the basement, but in the living room and up, the chimney is all brick, with an insulated stainless liner. BTW, price for the chimney is $9500. I asked the contractor to check the specs, but haven't heard back. He says the mason is doing a very nice job and it looks good. I guess I am just surprised and a little concerned about structural strength. Does the lack of block raise concerns?