Suspect Problem with my Chimney Cricket Design


#1

I bent and soldered up what I call a “triangular” cricket (ridge is not horizontal, but has a pitch which is the negative of the roof pitch - the ridge and the roof when viewed from the side make a symmetric “V.” The visible part of the cricket is comprised of 2 isosceles triangles).

On the roof side, the flashing flange is 8in but on the chimney side, it is only 2in. I was going to make it 4in, but somehow I changed my mind - possibly because at least 2in of step flashing should be covered by counter flashing.

The flashing is 4in tall and the joint with the 2in cricket flange is just all wrong in my book.

The consideration is that there is a dormer within 3ft of this chimney which means the total roof area that will generate water into the cricket is a 3ft by 3ft square area, which is basically nothing.

If the cricket counter lashing completely covers the 2in flange, technically it should be OK, but I still don’t like it.

Soldering more flange material is not going to happen. I was thinking these flashing tapes might be some insurance if I run 4in tape over the 2in flange and still completely cover the 2in with the counter flashing.


#2

Need some pictures. You saying you only have 2" Turing up the back of the chimney?


#3

Ya, only 2in up the chimney (what was I thinking…)!

The roof pitch is 7 in 12.

This is 24ga galvanized which is a real bear to work with. (Reason I’m using it a friend gave me (4) 4 x 10ft sheets of it. 2 sheets for the step flashing, 1 sheet for 4 aprons and cricket, and 1 for valleys)

I guess I could bite the bullet and solder in the corner piece where the “pinhole” exists between the cricket and top step flashing. (I’ve successfully formed a seamless external corner out of a 3in diameter piece of lead sheet - so I plan to have a positive seal (not reliant on caulking) at that point.)

I wonder how good these flashing tapes are? I could use a 4in or 6in wide tape on the 2in flange and extend up the chimney - still, the counter flashing would totally cover the 2in.

CameraZOOM-20171026095839794


#4

That should be alright. I would have went 3" but 2 is acceptable for step flashing.
If your working on it anyway, add a piece to wrap the bottom corners


#5

Looks like you got that galvanized way too hot.


#6

To add a corner piece, I’ll have to get the white paint off (Glidden Gripper which really sticks) and then there is the issue of he solder joint - a lap would be the easiest but could crack. When I did the V’s, I put a “double hem” on them so they would be the female and the cricket would be the male. Hemming he cricket is a PITA. I’d also have to do this after I finally fit to chimney which is another PITA since I’m doing this solo and dodging the weather.

My step flashing is 4x4x8 (using Metric dimensional/architectural).

I don’t know what exposure (if any) the steps should have when covered - doing dormers, a 2in exposure at the bottom is customary (hence the 4in.)


FLASHING TAPE:
Any comment on running 4in or 6in flashing tape over he 2in chimney flange and up the chimney? Seems like there is controversy over whether ice and water shield should be used around chimney. In my case, since the cricket is an unsupported part, if I I&WS underneath it, that I&WS will take the form of a simple, straight across pan flashing. ( I could install roughed out wood triangles to gie the I&WS a cricket shape but not close enough to support the cricket itself.)


TOO MUCH HEAT: (NOTE: what looks burnt is actually the edge of the paint that was nearby.) It is possible but I was dealing with unidentified rolls of solder from my solder collection and also probably the wrong flux. I ended up using dilute muriatic acid and what I think was 50/50 solder. I was using a 175w iron and could not find my 300w Hexacon iron but was getting frustrated with the slowness. I switched over to oxy-acetylene wth smallest aircraft tip (Smith AW1) and a carburizing flame.

I was nowhere near melting/burning the galvanizing off.

I think the proper flux also has some zinc compound in it. I would not argue that I over heated it. While I’m an expert auto body sheet metal gas welder, I’m still on he learning curve here.


#7

Spec for step flashing used to be 2" up the wall and 3" on the roof, with a 2" headlap.


#8

Galvanized, espically the some of the cheap crap they make today is hard to solder…have to pre tin it really good.


#9

This is old, vintage galvanized. From the basement of a generations old mom and pop local restaurant - they used it around the kitchen fryers. You can tell from the “weathering” that it’s decades old.

It actually soldered pretty good w/o flux - but not good enough to flow joints. Tinning would be no problem whatsoever so I didn’t bother. My problem was some of my joint ends were not tight enough so I had to build up solder to fill them.


Seems contradictory, but sheathing is supposed to be 1/2 to 1in from chimney and yet, they frame crickets touching. I’m going to cut up some 1by triangles to put under the the cricket for the I&WS. I’ll shoot for about a 1in gap bet ween the wood and galv.


#10

I just discovered sheet lead flashing and the ability to make “impossible” shapes:

CameraZOOM-20171112225344028[1]