Exterior Chimney Chase Construction

Fire stop at attic and roof deck.

Exterior chimney chase construction.

Above the chase height as per manufacturer. Framing the chimney chase. 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. Wood siding on chimneys wood shingles are often used as siding material for chimneys continuing from the roof area.

There are a disproportionate number of wood chimneys with rotted siding and wall sheathing when compared to other types of siding and other locations. Chimney chase a fireplace chase is essentially a knock out area of structure that hides a metal fireplace or cement blocks in a fireplace. Frame the walls on the roof assemble 2 together then stand each set and nail off corners of last two joints. 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.

Right since the chimney chase carries an insulated metal flue rated for zero clearance possibly actually requiring an inch or more of airspace and because the chase is outside the building it s not normally insulated. Keep minimum clearance from pipe to combustibles. Frame the chase so the bottom of the vent is. 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.

Typically uses 2x4 structural members sheathed with osb or plywood exterior building sheathing. Build chase of fireplace just like any other wall structure by placing its uprights between plates and top plates to create a large box.