Chase for exterior chimney?

[Badfish740]

I've never had draft issues even in the coldest weather with my chimney-it has two 90s within the first 6', but then it goes straight up for 21'. However, we'll be residing the house eventually and I'd like to enclose the chimney at the same time. Right now the chimney is lag bolted to the side of the house through the vinyl with 3" of clearance (I used a spacer). Obviously the house will be stripped down to sheathing, but where do I go from there? Do I just build a wooden frame around it with 2" of clearance all around? Should the inside be lined with something non-combustible (cement board, etc...)? The outside will be clad in Hardi-Plank.

 

[bholler]

yeah just frame it out no need for anything more what do you mean your chimney has 2 90s in it?

 

[Badfish740]

yeah just frame it out no need for anything more what do you mean your chimney has 2 90s in it?

Two 90 degree bends-A 45 out of the top of the furnace, 30" of pipe, 45, (I count that as the first 90) 4' of pipe out the window to a cleanout tee (second 90), then straight up for 21'.

 

[bholler]

Ok that is pretty standard then i was wondering i though you had 2 90s in the actual chimney and didn't know how you did that

 

[DAKSY]

Check the install instructions for the Class A chimney you have.
You are probably going to need to install a firestop every 8-9 feet if you enclose it in a chase.

 

[Warm_in_NH]

Please make sure your contractor knows the right way to install the siding and follows the instructions. You should also be well versed on the subject and inspect their work daily (just wait til they leave for the day)

The majority of installs I see are done wrong and fall apart after 5-10 years.

Do your research, don't bank on your contractor doing his. He'll just pass the buck to the company when it falls apart, they'll tell you it was installed improperly, he'll tell you his warranty is up, etc....see it WAY too often.