Chimney thru metal roof

[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.

 

[charly]

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!!

 

[jeff_t]

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.

 

[webby3650]

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.

 

[webby3650]

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.

 

[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.

 

[jeff_t]

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?

 

[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: (broken link removed to 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.

 

[webby3650]

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!

 

[webby3650]

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.

 

[jeff_t]

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.

 

[begreen]

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

 

[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.

 

[Heatsource]

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

 

[charly]

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..

 

[Bret Chase]

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...

 

[Bret Chase]

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....

 

[webby3650]

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.

 

[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?

 

[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.

 

[Bret Chase]

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.

 

[Bret Chase]

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...

 

[Bret Chase]

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.

 

[begreen]

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.

 

[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...