Preface....So I had my new insert installed around mid-Nov and have been burning just about 24/7 since. My typical burning rhythm is a full load every 8hrs; load up around 11pm, load up around 7am, load up around 3pm, and so on. When the stove is at the end of a burn cycle towards it's 8th hour, the stove-top temp is usually between 250-300 degrees. Then I load up, door cracked if need be for a few mins, air wide open, get the stove-top temp to 600 degree then scale the air back. Throughout the duration of the burn I would say the average stove-top temp is between 425-475 degrees. The wood I have been burning is all >20mc. The height of my chimney from base of firebox to top of chimney is 12'5". Yes, a shorty. My cap is a large, 3-flue metal cap. The clearance from the top of the chimney to the underside of the cap is about 6". Yesterday, for the heck of it, I got up on my roof to take a look at chimney crown, cap, etc. Flat roof, real easy to do. Well I was a bit shocked to see the underside of the cap coated in a significant layer of creasote! I did not remove the cap and look down the chimney because I was burning at the time. Is this something I should be concerned with? If the underside of my cap is coated, does this mean my liner is just as bad? The liner by the way, is single wall SS flex pipe with a double layer wrap of 1/2" insulation. I would really appreciate some feedback from some burning vets. Thanks guys.