Update: I finally stopped guessing on liner sizing and started measuring twice
I used to eyeball the flue and grab whatever liner was closest on the truck, which worked fine until a job in Portland last fall. The homeowner had a 9x13 clay tile that I swore was 8x12, so I ordered the wrong size and ate a 3 day delay plus $180 in return shipping. Now I measure the top and the bottom of the flue on every single job because they are almost never the same size. A sweep I know in Boise told me he has seen a 2 inch difference between floors more than once. The bottom is usually smaller from years of creosote and broken tile edges, so if you size off the roof you will be fighting it all day. Anyone else keep a cheat sheet of odd flue sizes they run into, or is it just me writing them on the truck dashboard?