jfd

Hi I have a question regarding a 6'' flue pipe coming off an of oil fired burner i want to run the pipe up 5' then run the 7' of horizontal run in between 2 floor joists I would like to surround the exposed wood of the floor joists and the floorboards with 2'' thermal fiber a firesafe insulation and then 1/2''cement backerboard over that screwed to floor boards and 2 side floor joists and then close the bottom with 1/2'' cement board so there is no combustible material exposed to any heat.Is this an acceptable solution for moving the flue pipe up and out of the way of the cabinets that it was running through before?The chaseway built in the ceiling will be open at the mechanicle room end to allow any heat to escape from the chase.The flue is connected to a chimney.It will be accessible for cleaning at the ceiling height Thanks for your thoughts John