Skip to navigation
TLCCSS — Cathedral Ceiling Support Box

How to Specify

Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design. The System Design and Installation Guide is an additional resource.

TLCCSS — Cathedral Ceiling Support Box


  • Used in pitched ceiling support installations.
  • Supports a total of 38 feet of chimney with up to 15 feet below support. Includes support clamp, allowing chimney pipe to pass belowsupport.
  • Matte black finish with stylish brass finishing trim and ceiling trim to cover rough opening.
  • Also acts as a firestop with use of trim plate.
  • 12/12 maximum pitch.


Available sizes (inches)

5TLCCSS5"7 1/811
6TLCCSS6"8 1/812
7TLCCSS7"9 1/813
8TLCCSS8"10 1/814