24" Ceiling or Roof Support Box

The 24" Square Ceiling Support Box provides safe passage of double wall chimney pipe through your floor or ceiling and supports the weight of the chimney in through the ceiling installations. The support box must extend at least 2 inches below the finished ceiling.

In case of a cathedral ceiling; The box top either gets trimmed, folded over and nailed to the roof for as a supporting flange; or it gets trimmed flush matching the roofline slope and anchored to box framing under the roof.

The Ceiling Support Box can support a maximum of 50-ft of chimney pipe and includes trim to provide a finished look inside the room.  The support box and trim is painted black to match the black single wall stove pipe.

Attached to the bottom of the chimney support box is a twist lock connection for the Stove Pipe Adapter to connect (sold separately).  The support box and trim is painted black.

The adapter section of our Ceiling Support Box's are made of 304 stainless steel while the box itself is made of galvanized steel (as it is not exposed to any corrosive elements).  

Ceiling Support Box: Areas of Use 

• Flat ceiling, no attic → 11"
• Flat ceiling with attic → 11" + Attic Insulation Shield above
• Vaulted ceiling with attic → 24"/36", trimmed to roof pitch + Attic Insulation Shield above
• Cathedral ceiling (no attic) → 24"/36", trimmed to roof pitch
• Multi-story house → 11" in the first ceiling above the stove (ground → 2nd floor)

Dimension Rules

The support box length must be longer than the TOTAL thickness of the ceiling / roof construction and must extend at least 2 inches below the finished ceiling.

This includes:

• joist or rafter height (actual size)

• additional nailers or battens

• drywall or ceiling finish

• roof decking (for vaulted/cathedral ceilings)

Example:
2x10 joist (9.25") + 2x4 nailer (1.5") + 1/2" drywall (0.5") = 11.25"
Required minimum including clearance below ceiling = 13.25"

→ 11" box is too short
→ use 24" (can be trimmed)

Why you should buy our Class A Flues

It is for use with free-standing wood stoves, fireplace inserts, fireboxes, fireplaces, furnaces, cook stoves, boilers, and water heaters.

• Additional Info
• Installation
• Deliveries
• Certification

 

Installation Instructions

Click on the buttons below to access installation guides and videos:

External Flue Installation Guide Internal Flue Installation Guide

Watch Video: External Flue Setup Watch Video: Internal Flue Setup

Delivery Information

We offer reliable and fast shipping:

• Standard Delivery: From stock, in 3–5 days
• Returns: Within 14 days of delivery

For more details on our shipping policies, click here.

Certification

Certified to meet UL103HT standards, ensuring high safety and performance for residential heating appliances that require a UL103HT chimney system.

 

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