I have a woodstove chimney install with an intermittent leak that I’m trying to solve. The material is Metalbestos Ultra Temp, which is stainless steel insulated pipe, 8″ O.D. The section going thru the roof/ceiling is installed, along with the metal roof. There’s a section of pipe going thru the roof, a roof jack, a storm collar, and a rain cap. The whole thing was installed on a small curb rather than just integrating the roof jack into the roofing panels.
Anyway, when we get strong winds and rain, a small amount of water comes in. It drips down the outside of the pipe on the downslope side. I finally risked my life and got up there today (steep metal is hell to get on…) and everything looks good, the caulk around the storm collar is intact, etc. What I noticed and am concerned about is that there are ventilation slots around the top of the roof jack. These are covered by the storm collar, but the bottom of the collar is about 1-1/4″ below the bottom of the vent slots, and I think this is inadequate when the wind gets howling (40MPH+, happens several times per winter).
Metalbestos does not make a “taller” storm collar, but I was thinking about buying the 10″ version and amending it to the existing 8″ collar with rivets, to extend the bottom edge downward.
Any other thoughts?
Replies
sounds like a plan -
wind driven water can do strange things -
these collars aluminum? - makes for easy modification -
or, cut yourself a cardboard template and just cut a brand new collar out of one piece of metal using the old collar as a guide - cleaner job - no rivets or caulk -
I think I've got your explanation, but wasn't sure what you meant by roof jack you are referring to the flashing that lays flat on your built up curb? It shouldn't need a curb if the correct parts were used. I contact the manufacturer before I do anything with a fpl, the insurance co's walk away if you do anything unapproved, and the manufacturers will send approved modif to you, .. that said it sounds as if you think the wind blown rain can rise up the jack under the storm collar, it you run a bead of high temp (red) caulk along the jack in front of the vents it might be enough to direct the water away from the vents ..
the other thing I've seen is the water being drawn by capillary action into the folded seam of the pipe, I caulk the lower part of the seam and pay close attention to where it and the collar meet ..
>>by roof jack you are referring to the flashing that lays flat on your built up curb? It shouldn't need a curb if the correct parts were used
The roof jack is the only style they sell for 6:12-12:12 roofs and while it would work great sitting on the deck if the roofing were shingles, it is not ideal for a standing seam metal roof. We constructed and flashed a small curb, and then folded the edges of the jack down to counterflash. As far as I am concerned it's a lot better than trying to make it sit flat on the roofing--I'd have to slit the adjacent roofing panels, slide the jack into the slits, and then try to conform the downhill leg of the jack over the roof ribs. I have seen it done with 5V crimp panels, it is an ugly, caulk-laden detail.
Anyway, the curb is fine, the leak is not there. I am going to talk to the factory tech and see what they recommend, but I pretty much need a bigger storm collar.
I made a chase 3'x6' for my pipe run due to the hole in the roof being there from the stone chimney. I capped it with a copper cap and made a collar that turned up 3'' and made my own storm collar.
Which I think you are contemplating. You just need to make a donut that is wider than what you have now. IIRC tho OEM has a bolt and captured nut to clamp the collar, I just lapped and riveted the one I made.
My gut feeling is that maybe the collar to pipe joint wasn't caulked well enough or has failed, I inspect mine when I clean the chim. and even tho' it is a an insulated pipe and way away from the stove, I can see the Lexel that I used kinda aging.
But making a new collar that is wider should be a pc. of cake. Just draw the pipe diam. plus an inch or two for lap and then go 4'' or so wider, cut it out of galv, or copper and wrap the pipe, clamp till you drill the first rivet and then add more rivets. Caulk with Geocel or Lexel.
I'd do that before I'd experiment with an addon to the existing on the downhill side only.Spheramid Enterprises Architectural Woodworks
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I had seen the same proplem as you when I was on the Coast of Washington. Rain blowing horizontally and then upward when it hit walls, roof and pipe. it is amazing how the soffits would be soaked on a 10' deep porch when there is driving rain.
The solution that I used was just as you have mentioned and that was to have a larger storm collar. Larger in diameter and a steeper angle. I dealt with a local metal fabrication shop and they could make anything I wanted in stainless. Prices were actually less than expected.
One thing a friend told me long ago was to never used the roof jacks that are for adjustable pitches. Have one made for the exact roof pitch you need. Seems to work so far.
I don't think the roof jack is really the problem or at least, if I made my own, I'd have to make the same vent slots in it and they'd leak. I'm not a big fan of making stuff for pipe systems, it is better to use only listed parts. In the case of a storm collar I see no harm. I am also probably going to make my own trim for the ceiling inside because the two piece deal they sell is so ill-fitting. It's my place, not a customer's.
That is a ccomon problem with metal chimenys because that has to be a slipin joint for venting and thermal expansion, but the wind dows inject a bit of moisture. A lot of people don't notie until spring when the fire goes out. If you only burn occasionally, you will see more of it too
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