Chimney Chase Cover

[Gareth96]

My old chase cover is a bit rusted.. I'm putting in a new woodstove that uses 6" vs 8" pipe.. So probably best to get a new cover.

Has anyone used one of the online chimney chase cover makers? Any recommendations, or best to have it done locally? Will probably go stainless..

Thanks!

 

[DAKSY]

We always made them out of sheet aluminum. Easy to work with. Bends nicely in a brake. 2" returns down all sides. Roughly 1/4" larger than the deck you're covering, to allow for any out of square conditions in the framing. Underneath, near the pipe, we'd place small strips of 1/2" durarock to force the center to be higher than the edges to allow for run-off. 2" high collar, goobed with copious amounts of GE Silicone in the center, smaller than the storm collar you're using. Entire assembly held in position with roofing nails through the 2" returns.

 

[begreen]

A good chase cover will have a raised rim hole or collar for where the pipe exits instead of being flat. It will be stainless steel and will have a generous folded down drip edge on the perimeter.

http://www.chimneylinerdepot.com/custom-chimney-chase-cover/

 

[NVHunter]

How do you vent a chase? I've seen on the duravent instructions that they have 1/2" spacers under the chase, and 1/2" to 3/4" space all the way around for ventilation.

Is this correct?

What other way do you vent a chase?

 

[webby3650]

How do you vent a chase? I've seen on the duravent instructions that they have 1/2" spacers under the chase, and 1/2" to 3/4" space all the way around for ventilation.

Is this correct?

What other way do you vent a chase?

I've never heard of venting a chase. Can't see it being possible or necessary.

 

[webby3650]

SS is the only way to go. Make sure it has a cross break, and a nice size lip with a drip edge. 2"-3" lip is best.

 

[begreen]

I've never heard of venting a chase. Can't see it being possible or necessary.

My main concern with venting a chase would be bees. Screen whatever gap you leave or you could have a serious bee problem if honeybees move in or a major hassle if wasps or hornets move in.

 

[webby3650]

My main concern with venting a chase would be bees. Screen whatever gap you leave or you could have a serious bee problem if honeybees move in or a major hassle if wasps or hornets move in.

There a hundreds of thousands of un-ventilated chases out there. And most of them have bees in there somehow. I can't imagine how bad it would be if they had easy access!

 

[begreen]

They only need a tiny 1/4" hole to access.

 

[BrotherBart]

Sitting in my basement office one night in 2007. When the African Hornets started coming in. Took a while to find the 1/4" space in the mortar in the double flue masonry chimney where they were getting in and working their way down to the basement.

A real interesting week. Found the nest in a tree thirty feet in the woods and took it out with a 12 gauge and number six shot.

 

[NVHunter]

I've never heard of venting a chase. Can't see it being possible or necessary.

This was what I saw and was referring too...

Don't know so that's why I'm asking.

 

[Gareth96]

I did the math, and if you have a 1/8" gap around where the pipe comes out of the collar of the chimney cover (for 8" OD pipe) you get about 6 sq in of venting there.. then 1/8" gap around your chase cover (2'x4') is another 18 sq in.. so 24 sq in.. that should be enough eh?

So what should an aluminum chase cover run me (2'x4' with one centered 8" hole)?

 

[DAKSY]

$150 max would be MY guess. 1/2 sheet of aluminum. One aluminum collar. One tube of GE silicone & 1/2 hour labor.

 

[Gareth96]

I e-mailed ICC since that's the chimney I plan to use... my chase is a wood frame chase built on the side of the house and is totally enclosed (even where it bumps up to the attic on the gable) up to the chase cover. The old ZC fireplace is going to get ripped out, and I'll build an alcove for a Blaze King Princess.. ICC said for this setup they recommend building a false ceiling above the alcove, with insulation over the false ceiling similar to an attic. The section of chase between the alcove ceiling and the false ceiling should be insulated like an exterior wall, and the chase above the false ceiling will remain uninsulated. No venting necessary.

 

[NVHunter]

I e-mailed ICC since that's the chimney I plan to use... my chase is a wood frame chase built on the side of the house and is totally enclosed (even where it bumps up to the attic on the gable) up to the chase cover. The old ZC fireplace is going to get ripped out, and I'll build an alcove for a Blaze King Princess.. ICC said for this setup they recommend building a false ceiling above the alcove, with insulation over the false ceiling similar to an attic. The section of chase between the alcove ceiling and the false ceiling should be insulated like an exterior wall, and the chase above the false ceiling will remain uninsulated. No venting necessary.

My setup is very similar. I'm going to be building it this summer however as it doesn't exists right now. I'm removing a natural gas fireplace and creating an alcove which extends 24" out the south gable side of the house.

The alcove is balloon framed 24" out of the main framing of the house and has it's own small roof on top. My chimney will exit this roof and will be framed in a chase up the side of the house to the gable eve and then up.

The alcove will have a ceiling where the pipe will go through, and up.

Is ICC stating to build another "false" ceiling above that with insulation between the two?

Then have the remaining part of the chase uninsulated with no venting?

 

[Gareth96]

Not sure if the link below is going to work because my internet blocker here at work is protecting me from evil... If it doesn't work, google 'Typical Chase Construction' and go to images.. quite a way down you will see a drawing of a chase that has 'Typical Chase Construction' at the bottom, the website is something like g2h3.blogspot.. But this is what ICC sent me.

It's for a fireplace, but they said same principle aplies. And yes, you will have a ceiling for your alcove, and then a false ceiling at about the height of the where the attic starts. If your alcove ceiling is the same height as the rest of the ceiling in the room, the false ceiling may not be needed?? Looks to me like the intent is to insulate any chase that is adjacent to living space, and any chase above living space is not insulated except for the top of the false ceiling. Hope this helps.

http://www.google.com/imgres?start=...t=rc&dur=710&page=5&ndsp=34&ved=0CHUQrQMwJThk

 

[Gareth96]

So first local estimate I got for a chase cover from a sheet metal shop.. Aluminum, 18ga, 63"x28", centered hole, cross breaks, 3" collar, 3" side drop, and drip edge.. $300.. Sound competitive, cheap, or steep?

 

[bholler]

I agree with begreen go with stainless we have replaced allot of 15-20 yr old aluminum ones because the rotted through

 

[DAKSY]

I agree with begreen go with stainless we have replaced allot of 15-20 yr old aluminum ones because the rotted through

I've NEVER seen an aluminum chase top rot thru.
Galvanized steel, yes...Aluminum, no...
You sure yours wasn't a galvy?
20 years ago, that's ALL they were made from...

 

[bholler]

yes aluminum the one development was all aluminum tops and yes they rotted through. It is pretty easy to tell the difference between gal and alum. We have replaced allot more galvanized ones. That development is the only place I have seen aluminum ones here. And most of them are failing.

 

[begreen]

I'm wondering if there is a galvanic reaction over time between the two dissimilar metals?

 

[Gareth96]

I thought about that (galvanic reaction), but was going to put a strip of door gasket material around the pipe, inside the collar of the cover to keep them from touching. But that all doesn't matter now.. I found a local guy that will do a Stainless Steel one for $200.. 24ga steel, cross breaks, collar, side drop, drip edge... the works.. Guy's been in business over 40 years, "don't do computers".. going to bring the measurements to him this afternoon if the weather holds up. Oh, and he was on the toilet when I called