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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.

How to Purchase

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 below support.
  • Matte black finish with ceiling trim to cover rough opening.
  • Also acts as a firestop with use of trim plate.
  • 12/12 maximum pitch.

Cathedral Ceiling Support Box dimensions (inches)

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

TLCCSS - Cathedral Ceiling Support Box - dimensional drawing