4-Inch Insulated Wall Thimble / Radiation Shield

This 4-inch wall radiation shield is the Selkirk insulated wall-thimble assembly used where a compatible 4-inch Model HT / Ultra-Temp chimney passes horizontally through a combustible wall. Selkirk identifies the 4-inch component as HT4WRS.

Current Selkirk literature describes the wall thimble as a telescoping two-piece assembly that provides the required airspace around the chimney and accommodates common wall thicknesses.

4-Inch Wall Thimble Features

• Chimney size: 4 inches
• Manufacturer: Selkirk
• Selkirk product code: HT4WRS
• Required framed opening: approximately 10-1/8 x 10-1/8 inches
• Wall thickness range: approximately 6 to 11 inches
• Interior finish: Black interior wall plate
• Purpose: Shields and spaces the insulated chimney at a compatible wall penetration

Why Use the Wall Thimble?

When a listed insulated chimney passes through combustible wall construction, the penetration needs the shielding and airspace specified by the chimney manufacturer. The wall thimble creates that controlled passage and helps prevent framing or finish materials from encroaching on the required chimney clearance.

This component is for wall penetrations. It is not a ceiling support, roof flashing, or attic insulation shield.

Related Through-Wall Components

• 4-Inch Insulated Chimney Pipe - 36-Inch Length
• 4-Inch Insulated Chimney Pipe - 24-Inch Length
• 4-Inch Wall Support Band
• 4-Inch Rain Cap

For other penetration types, see the Black Ceiling Support, Firestop Radiation Shield, and Attic Insulation Shield.

Read our 4-Inch Stove Pipe Guide or browse all 4-inch chimney and installation accessories.

Installation Notes

Use the wall thimble only in the configuration shown in the current Selkirk installation instructions. Do not pack insulation or other material into the required chimney airspace unless a manufacturer-approved shielding-insulation system specifically calls for it.

Wall construction varies, so verify the required framed opening, support, exterior chimney layout, weather sealing, and local code before cutting the wall.

For current manufacturer specifications, see the Selkirk Ultra-Temp chimney resources.