Did I screw-up my chimney install???

[DrivenByDemons]

So I built a new home and the guy at the stove store told me it would be no problem for me to install my own chimney for my new PE Spectrum. He gave me all the rules and some tips and away I went. I have an 8/12 pitch where the chimney exits the roof so I needed a pretty good length of pipe on the outside of the structure. I wasn't thrilled about the look of the supports I would need so the stove dealer told me I could build a chase instead of having poles come down to the roof. I did this and made sure none of my framing was closer than 2" (I think I made it around 4" to be safe). My question is about the top... I framed some 2x4's to make a 12"x12" square opening and used something like this "firestop assembly" to anchor it to the framing (I didn't use this specific brand, this link just shows a good picture of what I used).

http://www.americanmetalproducts.com/chimney/ameritec/hs.htm#fire

I stuck it over the pipe and used some roofing nails to anchor it down to the framing. I then had my HVAC guy make a cap onsite to cover the whole thing up. My question is, do I need to allow air to escape from the top of that chase I built? I noticed most of the roof flashing kits that come with these pipes have ventilation holes that get covered with a raingaurd of some sort so attic air can flow around the pipe and to the exterior. I don't have that happening right now. I'm also not sure this "firestop assembly" was the proper thing to use at the top but at the time it seemed perfect. The stove dealer was really acting like as long as your 2" away your cool but after reading some stuff on this site I'm starting to wonder if I screwed up...

 

[Shane]

If your particular brand of pipe has vent holes in the flashing you might want to replace your firestop with the flashing. I would call the tech dept of the pipe mfg and see what they say. Compared to some things that I've seen, you're probably alright, and if the pipe co. says your not it should be a fairly easy fix.

 

[Metal]

You need a Flat Roof Flashing with the holes in it if that is what the company used to have an U.L. Listed System.

That being said, one thing you can do is oversize the hole slightly in the chase cap then make holes in a storm collar and slip it over the pipe. Silicone at top and bottom of this storm collar. Next put an additional storm collar about an inch above the one with holes in it and silicone around the top of it. It is kind of a poor man's cone flashing.

 

[jtp10181]

Normally we would just run the pipe or through and use the chase top to hold it in place. No need for the firestop but it wont hurt anything.

 

[DrivenByDemons]

Cool, thanks for the replies. That oversize hole w/ the storm collar sounds like a great idea... I might give that a try...

 

[Metal]

I had condensation issues in my chase (on an outside wall) which rotted out the framing and drywall. When I fixed it I tried to allow it to "breath" by adding 2" round wall vents near the bottom and allowing air to escape at the top. So far it seems to be working nicely. The little vents can be bought cheaply at any big box store and all you need is a 2" hole saw and some caulk to install them.