# Chimney thru metal roof



## jeff_t

We bought a vacation place a few weeks ago, and I have a stove to install. Some brief searching hasn't shown me much for what to use to penetrate a metal roof. I found a silicone boot from Selkirk, but I'm not sure if that's what I need. We're taking a U-Haul full of crap in a couple of weeks, and I may be able to get the stove in, if I can gather what I need in time.

It isn't corrugated, it looks like this. I think. I have only seen it once when it wasn't snow covered.


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## topoftheriver

jeff_t said:


> We bought a vacation place a few weeks ago, and I have a stove to install. Some brief searching hasn't shown me much for what to use to penetrate a metal roof. I found a silicone boot from Selkirk, but I'm not sure if that's what I need. We're taking a U-Haul full of crap in a couple of weeks, and I may be able to get the stove in, if I can gather what I need in time.
> 
> It isn't corrugated, it looks like this. I think. I have only seen it once when it wasn't snow covered.
> 
> View attachment 91930


If you're not sure, it would be wise to hire a professional so you don't damage the roofing.  It is tricky to get the hole in the right spot.


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## jeff_t

I have done two installs through shingled roofs, so I'm pretty familiar with the process. I'm just not sure how to seal up the metal roofing.


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## begreen

I think you'll want to use the special flashing/boot for that job. Here's an article on how to and not to do this. Ping Hogwildz. He knows all things roofing.

http://www.mbci.com/pdf/published_articles/metalmagPipe_200507_final.pdf


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## jeff_t

begreen said:


> I think you'll want to use the special flashing/boot for that job. Here's an article on how to and not to do this. Ping Hogwildz. He knows all things roofing.
> 
> http://www.mbci.com/pdf/published_articles/metalmagPipe_200507_final.pdf



Thanks. 

I can see this won't get done in an already sorta busy weekend. I think I better put it off until summer.


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## begreen

Good idea, this is not a job you want to rush. Most importantly, remember that water wants to run downhill. Don't impede it by creating artificial dams of silicone where it isn't needed.


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## jeff_t

Good point. There's not much pitch to begin with.

The previous owners left us with 68% in the 500 gal pig . No hurry, I guess.  Probably should buy some wood, though.


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## Leroy_B

I'm going to follow this thread closely. I also wondered about a chimney flashing for a metal roof and how the install is done without any water damming up.


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## webby3650

I know some people use the silicone flashings with success, but I often find them leaking. In addition to the risk of leaking, they offer NO support for the chimney like a metal flashing offers. 
Anytime we do a metal roof install we use this one from ICC. It offers a permanent seal, it installs similar to a shingle type flashing, by tucking under the metal on the top side.

Here is the flashing to use: http://www.icc-rsf.com/main.php?t=chem_produits&i=95&l=en


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## Treacherous

I have this one.  No complaints here.



webby3650 said:


> Anytime we do a metal roof install we use this one from ICC. It offers a permanent seal, it installs similar to a shingle type flashing, by tucking under the metal on the top side.
> 
> Here is the flashing to use: http://www.icc-rsf.com/main.php?t=chem_produits&i=95&l=en


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## jeff_t

Maybe we should think about tearing the brick chimney down and go thru the wall. There is a ceiling support in place from a previous metal chimney, but they covered the hole when they put the new roof on. The exit point has to be almost at the peak. I'll have get in the attic and take a look.

The hearth that is there has a TV on it now


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## webby3650

Can you re-line the chimney thats in place?


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## begreen

webby3650 said:


> I know some people use the silicone flashings with success, but I often find them leaking. In addition to the risk of leaking, they offer NO support for the chimney like a metal flashing offers.
> Anytime we do a metal roof install we use this one from ICC. It offers a permanent seal, it installs similar to a shingle type flashing, by tucking under the metal on the top side.
> 
> Here is the flashing to use: http://www.icc-rsf.com/main.php?t=chem_produits&i=95&l=en


 
Good advice. Do you have any roof shots of an install?


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## webby3650

begreen said:


> Good advice. Do you have any roof shots of an install?


No, I usually take pics of the stove, but never thought to take a pic of the chimney.
I do a few a month through metal, I'll get a pic next time.


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## Bret Chase

flashing a metal chimney through a metal roof (screwdown or standing seam) isn't that big of a deal... if the hole stays in the flat and doesn't go through a rib.  If it's a standing seam roof is is generally better to use the silicone boot and figure out a different way to secure the top of the chimney, as a SSR is only restrained at the bottom, and grows toward the peak as it heats up.  With a screwdown it is also generally easier to use the silicone boot... though I have done a couple with a shingle type boot, but it requires cutting the panel....

if your hole transitions a seam in a SSR..... it becomes an ugly, ugly nightmare... the worst one I had to do involved 2 12" metalbestos chimneys that were less than 2' apart.... it took me almost 2 days to get it tight...


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## charly

topoftheriver said:


> If you're not sure, it would be wise to hire a professional so you don't damage the roofing. It is tricky to get the hole in the right spot.


When I went through my corrugated metal roof, I bought a stove pipe laser level that fits inside the top of the stove pipe or your wood stove and projects a laser dot right at the center point on the roof or what ever you are going through.. Was dead nuts on..scribed a circle after marking the dot and it was dead on plumb. I wound up using the silicone boot flashing kit..So far no leaks...


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## eclecticcottage

Just watching...we are thinking of doing a standing seam roof eventually, and we'll need to deal with this then.


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## begreen

Finally found a shot of the ICC flashing. I knew I had it sitting somewhere in my desktop junk.This is at the ridge, but the bottom detail is good. The storm collar has not been installed yet. Note that the sealant is only under the side flanges. The bottom is left unsealed for drainage.


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## chimneylinerjames

I would see what it would take to line the brick chimney. If its not in use, I would try to use the chimney that's already there. Just install a liner with insulation and your set.


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## Bret Chase

begreen said:


> Finally found a shot of the ICC flashing. I knew I had it sitting somewhere in my desktop junk.This is at the ridge, but the bottom detail is good. The storm collar has not been installed yet. Note that the sealant is only under the side flanges. The bottom is left unsealed for drainage.
> 
> View attachment 92111


 
the bottom detail isn't great....  is that a foam closure on the bottom, or was the metal cut to fit?


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## begreen

I think he wants to get the stove more centrally located with a taller, straight up flue. The brick chimney is pretty short. Add a couple 90º turns in the smoke path and it is going to draw poorly.


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## webby3650

Bret Chase said:


> the bottom detail isn't great.... is that a foam closure on the bottom, or was the metal cut to fit?


It's cut to fit. I seal the bottom edge though. The customer can see daylight and they don't like it.
And I don't think there would really be any drainage allowed due to the size of the hole only inches away from the tail of the flashing. On a shingles roof it makes good sense, but here, I would rather seal it.


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## Bret Chase

webby3650 said:


> It's cut to fit. I seal the bottom edge though. The customer can see daylight and they don't like it.
> And I don't think there would really be any drainage allowed due to the size of the hole only inches away from the tail of the flashing. On a shingles roof it makes good sense, but here, I would rather seal it.


 

I seal it when I install them in a metal roof... I don't care what the customer "wants"... They never seem to like the "I told you so..." I don't want the callback for the chimney leaking due to wind driven rain, or the ice damn that *always* happens just down hill of the chimney...


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## charly

begreen said:


> Finally found a shot of the ICC flashing. I knew I had it sitting somewhere in my desktop junk.This is at the ridge, but the bottom detail is good. The storm collar has not been installed yet. Note that the sealant is only under the side flanges. The bottom is left unsealed for drainage.
> 
> View attachment 92111


That's great if you can tuck the top under the ridge cap,, but that not always the case.


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## Lumber-Jack

begreen said:


> Finally found a shot of the ICC flashing. I knew I had it sitting somewhere in my desktop junk.This is at the ridge, but the bottom detail is good. The storm collar has not been installed yet. Note that the sealant is only under the side flanges. The bottom is left unsealed for drainage.
> 
> View attachment 92111


My roof install was very much like this except the chimney came out a little lower down from the ridge cap. All you have to do is cut another piece of the same type of metal roofing and install it so the lower part over-laps the chimney flashing and the top goes under the ridge. Done!


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## DexterDay

You own a King currently? 

What's going in the Vaca Home?

Congrats on the purchase also... Now is the time to buy, if your in the Market.


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## charly

Lumber-Jack said:


> My roof install was very much like this except the chimney came out a little lower down from the ridge cap. All you have to do is cut another piece of the same type of metal roofing and install it so the lower part over-laps the chimney flashing and the top goes under the ridge. Done!


Great idea!!


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## jeff_t

begreen said:


> Finally found a shot of the ICC flashing. I knew I had it sitting somewhere in my desktop junk.This is at the ridge, but the bottom detail is good. The storm collar has not been installed yet. Note that the sealant is only under the side flanges. The bottom is left unsealed for drainage.
> 
> View attachment 92111



That was going to be my next question, if it can be tucked under the ridge cap. Looks easy enough.

I'm not sure what the inside dimensions are of the existing chimney, but the outside is pretty small. I don't think lining is an option. And like begreen said, it's already a short one, so I'm trying to keep it a straight shot.

Dex, I picked up a used Spectrum last week, a craigslist find. And yeah, I was almost embarrassed by our lowball offer on the place, but it was accepted immediately.


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## webby3650

charly said:


> That's great if you can tuck the top under the ridge cap,, but that not always the case.


This flashing is made to tuck up under the existing metal roof, regardless if you are at the ridge cap.


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## webby3650

Bret Chase said:


> I seal it when I install them in a metal roof... I don't care what the customer "wants"... They never seem to like the "I told you so..." I don't want the callback for the chimney leaking due to wind driven rain, or the ice damn that *always* happens just down hill of the chimney...


Well if you read my post, I said I DO seal the flashing on the bottom side. And you should care what the customer wants, as long as it's safe, then it's no sweat!

And Ice damming and leaking rarely happens on the bottom side of the chimney flashing.


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## begreen

In this case I have to go by the mfg recommendation which is to seal the sides but not the bottom. If moisture gets trapped at the bottom it is going to invite rot. Make your notches clean and tight to the roof seams so that there is a very small gap and the customer shouldn't notice it.


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## jeff_t

webby3650 said:


> This flashing is made to tuck up under the existing metal roof, regardless if you are at the ridge cap.



So, it needs to go under the roofing that is under the ridge cap? The way it is done in the picture isn't right?


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## velvetfoot

I'm totally no expert, but...
I think I have a similar roof on my house:  it's a GrandRib3 by Fabral with the exposed fasteners.  I too wish it had been a hidden fastener arrangement, but that's how the house came.
Anyway, I was interested enough (who knows, maybe I'll do something, but I doubt it) that I looked it up.  Page 38 here:  http://www.fabral.com/assets/media/downloads/details-postframe.pdf .
All it talks about is pipe penetrations, but they have a boot that goes all the way to 13", and they show install details.  I can see that metal one being good, from a reinforcement point of view.
I can see that protection, reinforcement, for penetrating pipes, chimneys, etc, would be desireable for metal roofs with sliding snow.  That would be a good reason to get the stack as high as possible, I would think.
This is just me, the homeowner with no real experience, thinking.


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## webby3650

begreen said:


> Make your notches clean and tight to the roof seams so that there is a very small gap and the customer shouldn't notice it.


I make it tight. But you wouldn't believe what some people will notice. 
In an open attic, or cathedral ceiling install that little bit of light will get through and most customers will notice it. It's easier to just seal it.
Some will even complain about the light that is able to get through the seams in a cathedral ceiling box!


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## webby3650

jeff_t said:


> So, it needs to go under the roofing that is under the ridge cap? The way it is done in the picture isn't right?


It is designed to slip under the metal on the top side, with some careful cuts to the roofing. If its right at the ridge, then it can be done like the one in the picture.


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## jeff_t

webby3650 said:


> It is designed to slip under the metal on the top side, with some careful cuts to the roofing. If its right at the ridge, then it can be done like the one in the picture.


 
Sweet. I have the feeling that's where it will end up.

Can I use this flashing with other pipe? I wasn't planning on using Excel. This is something that will get used a handful of times in a winter, and I don't want to spend the big bucks. That flashing is the best looking flashing system I've seen, so I'll go with the Excel pipe if I have to. I guess I'd rather spend the extra bucks and not have the roof leak.


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## begreen

You should be able to use this flashing with another brand class A pipe as long as it is 8" OD.


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## Lumber-Jack

It seems to me the method of cutting a slit in the roof to slide that flashing under will leave a potential leak problem area on either side of where the flashing slides under the roof?
Installing a extra piece of roofing above the flashing so it overlaps it and extends up under the ridge cap would eliminate that potential leak source from cutting into the roof.

On another note, when I go in my attic I see light coming in around the flashing, but it doesn't present a problem. No more that seeing light coming in around the ridge cap. No water gets in at either place.


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## Heatsource

Anyone use lead flashing/solder job?
seems the most professional to me


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## charly

A1Stoves.com said:


> Anyone use lead flashing/solder job?
> seems the most professional to me


I thought that would be first class myself, but,,, I wonder about any chemical reaction with the solder and roofing metal being used. Would there be any corrosive issues down the road.. I'll also be replacing old standing seam and right now have the rubber boot set up through the metal..I think the boot is ugly... I'd rather have an all metal roof penetration... I also picked up a nice cricket that will go on the new roof from Obadiah's..


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## Bret Chase

A1Stoves.com said:


> Anyone use lead flashing/solder job?
> seems the most professional to me


 
about the only place lead is allowed these days is in a masonry chimney into a shingled roof... and I expect that to go away soon too...


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## Bret Chase

charly said:


> I thought that would be first class myself, but,,, I wonder about any chemical reaction with the solder and roofing metal being used. Would there be any corrosive issues down the road.. I'll also be replacing old standing seam and right now have the rubber boot set up through the metal..I think the boot is ugly... I'd rather have an all metal roof penetration... I also picked up a nice cricket that will go on the new roof from Obadiah's..


 
in a whole bunch of ways a silicone boot is vastly superior to an all metal penetration into a roof, especially when it comes to allowing thermal movement and acting as a thermal break....


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## webby3650

Bret Chase said:


> in a whole bunch of ways a silicone boot is vastly superior to an all metal penetration into a roof, especially when it comes to allowing thermal movement and acting as a thermal break....


Or, if that is what you are used to using. Just because you install one and walk away, and never hear from the customer again doesn't mean that they don't have issues.
It is not superior, I see leaks with them all the time.


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## begreen

The most important job of the flashing is a safe, weather-tite seal. There's no problem with thermal movement with a conventional flashing either. Is there a big need for a thermal break in this case? What is the advantage here?


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## charly

Mine actually developed a leak, it was on a raise rib metal panel..The fix,,, I unscrewed the bottom of the boot and filled the roof holes underneath with silicone,, it never leaked again,,,even though the directions said  to screw the bottom as well...I wasn't going to at first but did follow the directions,,, should have stuck to my guns...To me the silicone boot looks like an eye sore on a nice new roof,, just looks out of place to me,, like a patch job. Takes away from the clean lines of the roof, like someone threw a shovel full of silicone on the roof.


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## Bret Chase

webby3650 said:


> Or, if that is what you are used to using. Just because you install one and walk away, and never hear from the customer again doesn't mean that they don't have issues.
> It is not superior, I see leaks with them all the time.


 
I have installed several hundred of them... any leaks I have seen have been to because the trades (typically plumbers) push the pipe up, then pull it back down to set it back into the fitting inverting the boot... using a boot on a seamed class A chimney requires a bead of silicone around the lip, particularly where the seam is.


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## Bret Chase

begreen said:


> The most important job of the flashing is a safe, weather-tite seal. There's no problem with thermal movement with a conventional flashing either. Is there a big need for a thermal break in this case? What is the advantage here?


 
there is if you're trying to meet an overly stringent energy code... whether it actually amounts to anything or not is a whole different question...


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## Bret Chase

begreen said:


> The most important job of the flashing is a safe, weather-tite seal. There's no problem with thermal movement with a conventional flashing either. Is there a big need for a thermal break in this case? What is the advantage here?


 
if you've got a standing seam roof, and you're ok with your chimney being jacked back and forth a 1/2" by the roof, by all means, go for it.


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## begreen

Bret Chase said:


> if you've got a standing seam roof, and you're ok with your chimney being jacked back and forth a 1/2" by the roof, by all means, go for it.


 
If that is the concern, wouldn't the screwing down of the flashing, be it silicone or metal, be a concern? I would expect either to limit expansion.


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## Bret Chase

silicone will allow roof skin movement much better than the traditional metal flashing and storm collar, assuming it is appropriately sized.. i.e don't use a boot that is pretty much maxed out. With a silicone boot, you can use stitch screws and attach it only to the roof panel; which allows things to remain somewhat independent.  traditional metal flashings fix the roof and chimney to each other... and this causes the chimney to get rocked back and forth through the whole temp cycle... which in my local is pretty much a 115F swing. I don't particularly like using silicone boots, but in that application, it *is* what works best...


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## jeff_t

Finally got around to it. Easy peasy using the previously mentioned Excel flashing. This one fit right under the ridge cap. A few screws and a bunch of silicone to finish up.





Be aware that it doesn't fit Supervent pipe anywhere near tight. That gap took a bunch of silicone to fill. It is also pretty short, and since this is a weekend place, I am anticipating snow up past the flashing. We'll find out how good I did sealing it up.

I have some pics from webby3650 from one of his installs, showing how he cut it into the roofing. If anyone is interested, I'll try to repost them.


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## charly

topoftheriver said:


> If you're not sure, it would be wise to hire a professional so you don't damage the roofing. It is tricky to get the hole in the right spot.


They make a laser tool that fits right in your stove thimble or chimney pipe, projects a laser dot in the center on you roof or ceiling, so you know exactly where to cut.. i think I paid 100 dollars for mine, comes with 4-6 and 8 inch adapters . Takes the guess work out of where to cut the hole.


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## Hogwildz

You are going to install a storm collar on that right?


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## jeff_t

Hogwildz said:


> You are going to install a storm collar on that right?



I did. After I notched out the bottom of the flashing, screwed it down, and caulked it. I'm not sure it's totally necessary since this flashing isn't ventilated, but it is an extra measure of protection.


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## begreen

This has nothing to do with ventilation. A storm collar that is silicone sealed on the top rim is essential. Without it you will see leaks.


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## webby3650

You definitely need a storm collar, not an option.


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## Hogwildz

Where did you notch the flashing at? And why?
Storm collars are standard procedure.
Without them, as pointed out, you are very vulnerable to leaks.
And the collar must be caulked with good caulk where it meets around the pipe.


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## begreen

I'm guessing he meant here:


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