new stack

[cheesegenie]

OK, I took the advice from here and went all out and bought a "new" stainless stack and roof jack. It is 7" diam. and 15' long. If anybody
has time to answer some of these questions,it would help and be appreciated.
The roof jack has a flat base about 16" square and a ring. My roof is regular
galv. roofing with ribs. : will I have to cut a hole and try to drop the tin to
overlap at the centre of the jack? : how much clearance from the roof truss
is safe? How do you secure the stack to hold it up? Should the stack pipes be screwed together? Thanks in advace, I always get good advice here.

[cheesegenie]

I was also wondering if I use a bit of regular stove pipe at the top, will it cause rust that will damage the stainless steel stack? Again, thank you.

[Sugarmaker]

Cheese ..
Most everyone is tapping trees I guess,
I think you did the right thing getting sst stack. The roof jack should be installed so that water coming off the upper portion of the roof does not run under the upper edge of the jack skirt. so yes you might have to cut and lift the roof to slide the upper portion of the jack under the roof and the lower portion should be over the roof .
If 15 feet is 2 times your evaporator length and you are as least several feet above the peak then I would not add steel pipe. If you do have to add pipe I would recommend that you buy more stainless. Add a good flip up lid and you should be ready to go.try to keep the stack as far from rafters as possible or insulate the rafters with kiln insulation (blanket) and stainless covering.

If you add three screws in each section joint it should be very rigid and stand on its own. 15 feet is not that tall. You have the bottom on the arch you can put several screws in there if you feel you need to. The roof jack will keep it vertical.

Chris

[cheesegenie]

Chris, thanks for that info. I figure the stack will be about 3-4 feet above the
peak of the roof. I have 10' walls and 6/12 pitch ,so draft should be good.
Next year I hope to get or make a flip up stack cover.
Eugene

[tapper]

Cheese,
Try to maintain 18" from outside edge of your stack to any nearest combustible.
This means cutting out and heading off your trusses or rafters but better to put some time and effort to this now than have an unwanted event.
I also bent up and suspended tin and held it 1" from my rafters.
The 1" creates an air space against the wood and stays nice and cool.
Do not attach tin directly to the rafters that will transfer the heat to the wood.
Insulation is ok between the tin and wood but not really needed.

[jtthibodeau]

Just in case your not used to construction, maybe I can help a bit.

Use a plumb bob to determine the center of your chimney and where it contacts the roof. Mark out the diameter of the tapered flange to the underside of the roof. A small level held vertically may help you with the markings.

Cut the circle out with a reciprocating saw ("sawzall") or, what ever you may have. Once the hole has been cut, slice 2 equal horizontal cuts from the edge of the hole at it's widest or midway point. The total outside length of these cuts should equal the width of the flat section of the flange of the roof jack. A metal saw blade attached to your skil saw will make this part easier.

Just lift the upper section of the roof and slid the flange up into position until the flange strikes the upper roof section. There will be some stress due the the roofing being out of alignment by the ridges. You may have to attach the upper interior flange to the underside of the roof using self tapping screws or pop rivets. The same may be said for the lower section also. Just make sure all holes are sealed, as well as the far ends of the horizontal slices.

The chimney manufacturers also make supporting brackets for the insulated chimney. However, if your Sugar House is not constructed using normal construction practices, these supports may be difficult to work with or, need additional creative engineering!?!

[cheesegenie]

Thanks Jerry and Jon, that is some very useful information for me.
Eugene