Using a ZC chase cap for an alcove install

begreen

Mooderator
Staff member
Nov 18, 2005
84,216
South Puget Sound, WA
A neighbor has removed a ZC fireplace and is doing a DIY, alcove install in its place. The chase cap has a 13" opening hole with a 2" high rim that they'd like to keep. It's a big cover and still in good shape. What would you recommend for centering the new 6" chimney pipe in a watertight fashion at the top of the rim? I was thinking of a flat metal donut, 8" ID and 12" OD. They will need to get this fabricated. Are there off the shelf solutions or other ideas to do this correctly?
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,216
South Puget Sound, WA
A large storm collar would work.
We talked about that. Does anyone make an oversized one? What keeps the 8" OD chimney pipe centered in the 13" hole?
FWIW, I suggested they price out a new cap, though it is huge, from Rockland. Looks like that would be a $500 option but it would be stainless. The current cap is galvanized but in good condition. Guessing it's circa 2000.
 

DAKSY

Patriot Guard Rider Moderator
Staff member
If your neighbor takes a regular storm collar to a metal shop & tells them what he needs,
one could be fabricated from either sheet stainless or sheet aluminum. I made a raincap
for a bird feeder a couple of weeks ago, using a storm collar as a pattern.
I simply expanded the dimensions to fit what my needs.
Another option would be to stack a series of increasing storm collars.
Northline Express makes them special order...

 

DAKSY

Patriot Guard Rider Moderator
Staff member
This is what I fabricated from a piece of aluminum sheet.
The storm collar need b.y your neighbor can be made similarly.
In order to center the 8" pipe in the 13" collar on the chase top,
it may be necessary to zip screw the storm collar to the top &
seal the screw heads with 30 year silicone...
 

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bholler

Chimney sweep
Staff member
Jan 14, 2014
22,130
central pa
I would use a flat roof flashing kit. Possibly cut it up and only use part of it. But it should work
 
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begreen

Mooderator
Staff member
Nov 18, 2005
84,216
South Puget Sound, WA
I would use a flat roof flashing kit. Possibly cut it up and only use part of it. But it should work
I had thought about that. Not sure if the OD of the bottom part of the cone fits correctly over the flashingl rim, but it's worth looking into.
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,216
South Puget Sound, WA
If your neighbor takes a regular storm collar to a metal shop & tells them what he needs,
one could be fabricated from either sheet stainless or sheet aluminum. I made a raincap
for a bird feeder a couple of weeks ago, using a storm collar as a pattern.
I simply expanded the dimensions to fit what my needs.
Another option would be to stack a series of increasing storm collars.
Northline Express makes them special order...

If they decide to make the current cap work that could work out. The cap is not great. It has no drip edge or flare out to divert water away from the chase. I think I noted some rot at the top due to this, but I was looking up from the ground.
 

AlwaysStacking

New Member
Aug 25, 2020
4
CNY
It may be worth looking into having a welding shop add on material to get the desired hole dimensions. It could end up being close to the price of having a piece made up that you have to struggle with getting installed the way you want. At the same time they could add a drip edge or any other features.