Building A Chimney Chase

Chimney chase fire blocking requirements.

Building a chimney chase.

Framed chimney chases seem to be especially vulnerable and i ve repaired a lot of them over the years. Fire blocking perhaps 3 4 thick plywood or osb fire rated is intended to slow or even prevent the movement of a chimney chase fire between building floors and to prevent the increase of fire intensity and spread by the chimney effects that would occur inside the chimney chase without fires topping. 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. In addition to some structural improvements we used low maintenance pvc corner boards a.

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. It must be finished properly inside and out. A chase is a small enclosed space which is used to accommodate piping duct work or other utilities in home or building construction. A chase is usually built within a wall or ceiling and isn t visible to the eye although sometimes a chase protrudes from a wall due to structural necessity.

Chimney chase a fireplace chase is essentially a knock out area of structure that hides a metal fireplace or cement blocks in a fireplace. Renovation of a chimney that has leaked through to the roof sheeting. For example the house shown here was built just a few years before my crew and i began working on it but already the paint was peeling from the fiber cement clapboards and the corner boards had begun to rot see image 1. It must be high enough to protect the pipe in accordance with alpharetta building codes.