Expert: Steve Tavares - 11/14/2009

Question
I am installing a wood stove using a 6" pipe into a 7" flue thimble.  I have been advised by a friend to use mineral wool to wrap the 6" pipe to make up the difference in size.  I don't know what mineral wool is.  I know it comes in a roll similar to insulation.  Is it installed with the foil outside or on the inside?  And is it a good idea to fill up the 1" difference with mineral wool?

Answer
Nothing is supposed to be touching the chimney. The insulated chimney requires a 2" Clearance. The stove pipe will require a 6" Clearance if Double wall or a 12" Clearance if it's single wall.

What you will need is an adapter to go from the 6" to the 7" then go into the thimble. This is the way it should be done.

Hope this helps.