Fireplace Attic Chase

We also recommend to insulate the ceiling of the chase just as if it were in the attic space.
Fireplace attic chase. As currently designed the distance inside the chase to the chimney or firebox will be more like 24 on average with the closest spot about 6. A chimney installer indicated that i would need a firestop in this chase between the first second floor and another one 8 feet up from that. My builder is saying that there is no requirement for a firestop since the chase and pipes are on the outside of the house with no floor or attic floor penetration. The interior of the chase has plenty of clearance to the fp and chimney.
The chimney chase top chimney chase cover is usually metal constructed of formed aluminum or stainless steel. The rsf manual in the section about chases though they mean outer wall chases says. We find leaks here especially where the top is framed and enclosed flat and the top flashing lacks adequate pitch and stiffness to avoid collapsing even becoming concave where there are snow loads. Inspecting the firebox clearances is more challenging.
Seldom do we think about the fireplace metal vent pipe running up through the attic and roof. The manufacturors recommendation is 1 from the fp and 2 from the chimney to combustable materials. After you know where the penetration point will be for both attic and roof add 2 to all sides. Any wood that is too close to the chimney will undergo a process called pyrolysis and even catch fire at temperatures as low as 200 degrees.
The base of the chase must accommodate the framing dimensions of your fireplace. If the climate in your area is very cold insulate the chase to the top to keep the chimney warmer increase the draft and reduce creosote buildup. Fire stops are self describing. You can also taper the chase above the fireplace.
They are installed to stop a fire in the chase area where the vent pipe runs through to get to the roof. Measure the height of the furthest point of the installation. Most of the units inspected by chimney professionals are improperly installed and a trip to the attic to check clearances is definitely time well spent. Smaller dimensions for a rough frame of a chimney chase are about two square feet.
Climb into your attic and locate where your chimney system will enter this space.