Installation of Class A steel Chimney, roof question

[joecool85]

I have a asphalt shingled roof that I will be cutting a hole in to pass through the Class A chimney system I'll be installing next weekend (Oct 1 and 2). First, what's the best way to cut the whole through the roof? Second, what should I use for "sealant" around the flashing? What about on the storm collar, anything there?

 

[clutch25]

I have had good luck with a sawzall and a metal/wood blade. Use some copper RTV (ultra high temp) on the storm collar and roofing tar on the shingles you have to loosen...and yes, I know....don't tar the downslope side of the flashing...sigh...

 

[humpin iron]

GE 2 clear silicone. Weave the flashing into the shingles. NO sealant should show on flashing, water tight and out of sight.

 

[bpm44]

As long as you use the appropriate blade, a jigsaw, sawzall or even a circular saw will go thru the roof shingles and deck. I used a rockwell multitool and cut from the inside out. It was tight quarters and the thing worked like a champ.

For sealant I like both the Rutland and Imperial brands of high temp silicone for the chimney components and for the asphalt shingles I like the liquid nails roof repair sealant that comes in a caulking gun tube.

+1 on weaving into the shingles, but since I'm not a pro I used the liquid nails for extra security. No leaks yet - knock wood

If you haven't already read it, caulk the vertical seams on all exterior exposed class a pipe as well. They seem to be a big source of leaks.

 

[WES999]

Here are some pix of my install.
https://www.hearth.com/econtent/index.php/forums/viewthread/28385/
https://www.hearth.com/econtent/index.php/forums/viewthread/28386/

I used a 2" wide level placed around the chimney to mark the hole to be cut in the roof ( the hole needs 2"clearance around the pipe) , drilled a bunch of holes and cut with a sawzall.

I used polyurethane roofing cement to seal the flashing and Rutland hi temp black silicone to seal the storm collar. No leaks

 

[mhrischuk]

Here are loads of pictures of my install...I used a sawzall.
http://www.getdieselpower.com/misc/Sharon/Wood-Stove1/Equinox/CeilingHole/album/
http://www.getdieselpower.com/misc/Sharon/Wood-Stove1/Equinox/SupportInstall/album/
http://www.getdieselpower.com/misc/Sharon/Wood-Stove1/Equinox/ChimneyAssembly/album/

 

[joecool85]

If you haven't already read it, caulk the vertical seams on all exterior exposed class a pipe as well. They seem to be a big source of leaks.

Really? I hadn't heard this at all. Any here have any problems with this?

 

[mhrischuk]

Only the mechanically folded seams. They can be a water raceway. My Class A has welded seams.

 

[joecool85]

Only the mechanically folded seams. They can be a water raceway. My Class A has welded seams.

Huh, I'll have to check when I have. It's the Simpson Duravent DuraPlus triple wall Class A stainless.

 

[bpm44]

Didn't mean to scare you by saying "big" source of leaks, more like the non welded pipe seams were often the culprit in "mystery" leaks cases.

There were some threads on this about 1-2 months ago when I was reading up for my 17vl install.

Good luck and happy burning.