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Flashing this chimney/siding Intersection

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bilskro

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Discussion starter · #1 ·
Trying to figure out how to flash this chimney properly. Rain just runs down the roof onto the chimney and then gets behind the siding. In the photo I already moved the ¾” trim board that ran down the chimney. The only thing stopping water from getting behind it is caulk.

I am not sure how to flash it properly. I am thinking L Flashing. I can grind the chimney down a bit to make it flat I think for the L-Flashing. That way it will be L-Flashing with siding coming down onto the L-Flashing like at a roof line. The problem is what to bed the L-flashing in that will stop water from getting underneath it; Tar, Geocel, Thinset mortor or something else?

Or is that a bad plan. Any suggestions appreciated.
 

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#3 ·
the important part is where the water goes after it hits the flashing,a good quality caulk under the L should work fine to keep it out ove the angled part of the shoulder but i would grind a slot at the top a little to get the flashing to catch any water that hits the upper corner and bring the angled flashing down far enough to drain the water over the top of the siding or add a kickout diverter,which one would depend on the siding type
 

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Discussion starter · #4 ·
I have seen them do that for chimneys. Let me ask what is the concept of the reglet. I cut a kerf in the stone and then bend the metal to go int the kerf. And then caulk at the kerf where the metal and stone meet. So it is still caulk stopping the water. Is the concept that if water gets behind the caulk it will run down the kerf and not get to the wood studs and etc. Or is the idea that that caulk will be better than just caulking the bottom of the L-Flashing
 
#5 · (Edited)
well it does a few things,first it's a way to secure the metal it is also a ''break'' in the flow and it provides an area to install a sealant

there are times like when the shoulder is corbeled i will cover the area with metal,notice the upper j channel sits before the up bend of the flashing

while you can cut the reglet i personally don't think that's necessary on the angle you posted
 

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Discussion starter · #6 ·
Tom, I want to make sure I am understanding you.

The problem is water is getting behind the siding where the stone is. I would be putting the L-Flashing behind the siding and cut the siding to be at least 1" above the L-Flashing. So water runs down the siding and onto the L-Flashing. But water from the roof is dumping on the chimney and getting behind the wood and caulk that was there.

I am not sure if I put an L-Flashing with caulk under it that is enough. that is why I am thinking kerf on the stone that is angles down.

If I understand you correctly I do not need to cover up the entire stone work like your photo showed. And I do not need a kerf coming down the angles stone part. That simple L-Flashing with caulk under it would be good enough. But you recommend I take the flashing up the wall on the straight down part and cut a kerf and bend some flashing into it.

So basically it would be like your photo with the copper if the copper only extended 1.5" or so along the stone part.

Is that correct. Hmm, now I have to figure out how to make the up bend and not have a hole in my metal in the corner.
 
#7 ·
no no..look you are the one there,if you feel a reglet is needed then by all means do it,from your pic it looks to me like the stone on the angle [corbeled] part looks higher where it meets the wall than at the center and looks relatively flat so you could get a good seal

where i would cut a reglet is where the angled flashing meets the vertical stone so the metal is actually a little past that intersection
 
Discussion starter · #8 ·
OK, I think I get what you are saying. The problem is it is not as flat as it looks. It does go up a bit at the wall, but it also bumps up at the top corner by the siding side. It is not like the L-Flashing will lay super flat and slope down to the middle. But I was going to try and grind a bit and see if I can make it lay flatter. Would you use Geocel or OSI or just 40 year DAP caulk under the L-Flashing?

BTW if I can get it flattish sloping to the center of the corbel then your method would be the easiest.
 
#9 ·
geocel 2300 is my go to,i would clean the area and press the metal in to a heavy bead,bending the flashing a little less than 90 will give a pressure bend when you push it down,just try to keep it angled away from the wall

maybe lead would work better but i have never used it

like i said before imo where you dump the water that the flashing diverts is important,extending it past the vertical sections of the chimney and out to day light
 
Discussion starter · #10 ·
Saw this video on flashing the shoulder using lead.


I was just worried if lead or other material with no nails holding on the stone shoulder part and only caulk underneath would hold. High winds and hail and etc. would not get under and pick it up a bit weakening the caulk hold.
 
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bilskro
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