I'm ordering a chimney chase cover. I'm using their form. It states to add 1/2" to the actual hole diameter for the existing flue pipe size so the new collar will fit over it. My hole size is 15". That means I should use 15 1/2". No problem.
Then it says to add 1/4" to the actual dimensions of the chase so the flanges will drop down over it. No problem.
The difficulty lies in the last bit of instructions. https://www.rockfordchimneysupply.com/chimney-chase-covers/stainless-steel-chase-covers
I explained to the tech that if you follow the diagram and notes, you are making the hole size 1" smaller for every 1/2" you add to each side locating dimension. He insisted it was making the hole bigger. No, it will be smaller. Not sure how that part of math is so hard.
Then it says to add 1/4" to the actual dimensions of the chase so the flanges will drop down over it. No problem.
The difficulty lies in the last bit of instructions. https://www.rockfordchimneysupply.com/chimney-chase-covers/stainless-steel-chase-covers
I explained to the tech that if you follow the diagram and notes, you are making the hole size 1" smaller for every 1/2" you add to each side locating dimension. He insisted it was making the hole bigger. No, it will be smaller. Not sure how that part of math is so hard.