I’m looking for some advice on building a wood framed chimney chase. Here’s what I would like to do. Free standing wood stove pipe will go thru an ICF wall then vertical (double wall stove pipe) along the outside of a single story home. I figure the pipe and chase will have to extend 6-7 ft above the eave. Hole for pipe in ICF wall is already there (centered between two trusses). Attached is a pic showing the exterior of the house with the opening (square) for the stove pipe. Also, what type of base support (foundation?) would I need. I will be getting a building permit for all this.
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A heck of a lot depends on what type of stovepipe you're using.
Since presumably you didn't install a footing for the chase when you laid the foundation, probably you're better off attaching the chase (which is quite light unless you brick over it or some such) to the side of the structure and avoid having to dig in a footing.
The pipe will be double walled, I believe DuraVent. Right, I do not have a footer and I plan to cover the chase in light weight artificial stone veneer.
similar fireplace hee
We have a similar situation, sort of. The two-walled SS chimney for our steel fireplace is cantilevered on floor joists extending past the exterior wall. Actually, the fireplace is supported on the same joists; that means the SS chimney is a straight shot up from the fireplace, avoiding 90 deg bends. The carpenters just framed the chase using 2x and exterior plywood, then faux brick was placed on the outside (I don't know what kind of treatment the plywood had). Also, the faux brick is not pointed (it probably should have been). Eighteen years ago, I built a pent roof to protect the house door located just under the chimney. I flashed the chimney to roof joint with copper and never had a leak. But I had to remove and rebuild the pent roof when I replaced the siding two years ago, and this time, the flashing somehow allowed water to enter and drip below. I started putting caulking in the chimney's grout spaces, and had to "grout" in that way for several courses before I finally stopped the leaking. I figure that I was just lucky with the copper flashing the first time, and must have failed to bend a long-enough tab in the copper flashing to reach all the way to the back of the bricks' grouting line, plus failing to get enough silicon caulking into the grouting space.
All to say, you should use a waterproof grout in your faux stone, because without grouting, a strong rain will easily force water behind the stone and allow it to run down until it finds a way into wood.
Sorry for the long digression.
You don't need foundation for that chimney. Visit hvac store or website and look at the catalogues for possibilities. Wood stove seller websites also have catalogues and pictures. Your pipe will need sheetmetal firestops wherever passing through the house frame. Insulated double pipe require less distance from the combustible material. Your chimney has to be tall enough where the top of the chimney is level 10 feet away from the roof surface, or taller than the ridge. Wood stove forum posters often talk about walls that get scorched following the minimum code requirements. You also may need a part at the bottom of the pipe to catch the ash.
You need permit for this. My inspector, although passing my own design, did not like HO installed chimney used only for the furnace and water heater venting.
Wood stove venting may not allow for 90 degree turn, or allow very short turns only. I would not use 90 degree turn even if allowed, for easier cleaning, in which case you need oval hole through the frame as well as matching fire stops.
Thanks all for the advice and comments. I've been out of internet range the past few days.