Exterior Chimney Chase Construction

Framing the chimney chase.

Exterior chimney chase construction.

Typically uses 2x4 structural members sheathed with osb or plywood exterior building sheathing. Keep minimum clearance from pipe to combustibles. 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. Chimney chase a fireplace chase is essentially a knock out area of structure that hides a metal fireplace or cement blocks in a fireplace.

Above the chase height as per manufacturer. Build chase of fireplace just like any other wall structure by placing its uprights between plates and top plates to create a large box. If your home has a wood chimney chase with wood lap siding you need to pay special attention to it. Wood siding on chimneys wood shingles are often used as siding material for chimneys continuing from the roof area.

Crickets are more reliable particularly in climates where snow can accumulate and lead to ice dams. Frame the walls on the roof assemble 2 together then stand each set and nail off corners of last two joints. There are a disproportionate number of wood chimneys with rotted siding and wall sheathing when compared to other types of siding and other locations. The exterior of the chimney may require tuckpointing or replacement of siding materials to provide the best protection against moisture intrusion into the roof and interior structural materials.

For wind resistance if the chimney chase is passing through the roof structure rather than abutting the roof structure end it should be framed continuously through the roof structure not simply tacked on top of the roof sheathing. Frame the chase so the bottom of the vent is.