Building A Wood Chimney Chase

Kickout flashings we always install diverter flashings wherever a roof intersects a wall.

Building a wood chimney chase.

Called kickouts these keep water from running behind the cladding below and into the wall assembly see images 1 2. To build a fire retardant chimney chase one might use fire retardant plywood and sure one could try spraying a fire retardant coating but those are not common practices. Chimney chase a fireplace chase is essentially a knock out area of structure that hides a metal fireplace or cement blocks in a fireplace. Now that the frame has been completed guess who gets to clean up all that mess.

One solution is to install an insulated and sealed chase and to vent it to the interior so warm air can circulate. Make the chase enclosure airtight chimneys built on an outside wall whether exposed or boxed with a chase are prone to backdrafting. For chimney chases built into gable walls we install a partial diverter see image 2 again extending the sloped surface several inches beyond the corner see image 3. Codes allow a maximum of 90 degf temperature rise above ambient inside the the chimney chase well below the combustion or pyrolysis point for plywood.

Typically uses 2x4 structural members sheathed with osb or plywood exterior. Common specifications construction details for a wood framed chimney chase dimensions for a wood framed chimney chase may be as small as 24 deep x 36 wide but are more typically 3ft x 5ft x.