Chimney Flashing


#1

The chimney I’m dealing with is in the middle of a valley. The front of the chimney is not at the lowest slope, but the right corner of front is. So I plan to install a soldered copper “apron” corner piece.

My questions:

  1. How to install a copper step flashing? I would nail the back outboard corner so it’s overlapped by the next upslope step flashing piece by 2 inches. The first step flashing piece after the apron needs to be nailed in front outboard corner?

  2. How big step flashing should be? NRCA recommend a minimum of 7 inches long by 8 inches wide (bent in half). Would it matter if it’s bigger?

  3. I’m temping to use roofing cement or silicone sealant as a precaution to prevent water from getting into chimney thru step flashing. What is best to seal nails into step flashing? Some people said yes and some said no.


#2

Cut your reglet for the counter flashing.
Since you are using copper it will be easy to solder up the corners real good.
Stepflash as usual, using copper nails where they penetrate the flashings.
Make sure your upper and lower corners have a good solder joint.
Prime the chimney with asphalt primer, install counter flashing.

There should be Ice & water shield around the chimney also, wrapped up the sides of the chimney 4"-6", it will stick to the primer.


#3

Roofer, can you post a picture of that chimney?


#4

Sound like many I’ve done. Front corner in the valley?
Run up to chimney, Install apron. Bring upper valley down and fold it up the chimney. Con’t cut it less than 2" from the corner. Flash normally.
Ice and water is an option, but not necessary if done right.


#5

BBCode wouldn’t let me post my pictures. How can I solve this?[/code]


#6

Gallery tab at the top of page has instructions.


#7

Axiom,
How do I solder joint upper & lower corners? This is something I’ve never done before. Asphalt primer sounds like a good idea. I will pull back the ice & water shield and prime the lower chimney.

I also installed a bigger cricket for the rear end and rear sideway facing the valley. It should help guide the water around the chimney better. Thanks.

Tinner666,
Yes, front (right side) corner is in valley. The rear corner is away from the valley. The chimney has a rectangle shape. I plan to use closed valley method, with a bigger cricket in rear and back sideway facing the upper valley. Thanks for any advice.


#8

Not quite the same. I did this without solder or Ice and Storm shield.

http://www.rooferscoffeeshop.com/show_album_photo.asp?userid=30&albumid=132&file=1119&s=6


#9

I just noticed you mentioned overlapping a step by 2".
Don’t be afraid to overlap 4" if necessary! And/or use steps 9+" long if necessary. Use logic, not ‘rules’ of thumb.


#10

http://www.roofing.com/images/topics/6314/img_1206415159.jpghttp://www.roofing.com/images/topics/6314/img_1206415298.jpg�tween%


#11

Here’s a drawing of a new cricket that I made. The drawing looks bigger than it really is. It wasn’t perfect but it’ll do. My worries is when I put a copper step flash around the corner at the end of cricket where the water comes down. I think it’s gonna be tough to do. Any advice?


#12

Here’s a drawing of a new cricket that I made. The drawing looks bigger than it really is. It wasn’t perfect but it’ll do. My worries is when I put a copper step flash around the corner at the end of cricket where the water comes down. I think it’s gonna be tough to do. Any advice?

Honestly it looks like you have the right idea. Just make sure you lock everything and solder it and you should be fine.

Tinner, wtf man?! Putting tar in brick? That’s disgusting. You take mortar out you put mortar back, sheesh.


#13

Tar Monkey,
When you said “Lock it and solder everything”, do you mean “seam the copper step flashing”? I plan to go with closed valley method. The step flashing will be 4 inches wide hanging down from the chimney/cricket. The valley will be covered with shingles. So, I’m not sure what you had in mind when you said “Lock it and solder everything”? Please explain further.


#14

Cutting reglets aren’t really necessary. Looked better after I painted it, but paint hide details.

Tarmonkey is telling you the seams need to be flat-locked, or double locked before soldering. Laying metal on metal and soldering is only good for the short term.
Solder isn’t necessary though.


#15

Roofer, are you using copper for the cricket like this?

%between%http://www.roofersreview.com/d/9502-2/Stucco+chimney+cricket+flashing.jpg

Or something like this?

http://www.roofersreview.com/d/9503-2/Shingled+chimney+cricket+.jpg

If you get snow and ice, I suggest the copper. If you only get rain, I suggest the copper.
If you plan on the second example, ice and water shield and caulk the heck out of it, and pray it doesn’t rain.
For the copper, run the step flashing up to the corner, then a step around the cricket corner(under where the bottom of the cricket pan will go)solder these together. Install the lower counter flashing under/behind the cricket pan,install the cricket pan 2-3 inches past the chimney.


#16

Well, as long as we are all dropping our pants…

If you want to see how to do copper right invest in a book called ‘Copper and Common Sense’. I suggest locking and soldering all seams, pre-tinning is good to.


#17

Very nice saddle Dennis.


#18

Tar, that had to be a major PITA.

I like how you covered the brick steps. Nice job.


#19

I think Im going to use youse guyses pictures and sell some copper work :smiley:

Tar, is that copper only, or did you build a structure underneath?


#20

No, there was nothing there before. The mansard ran down into nothing. I had to build a cricket around three sides of the chimney with 2x4 and 5/8" plywood. They must have built the roof and chimney at the same time because I couldn’t even have put a nail in the last 2-3 courses because there was no room to swing a hammer. Things that make you go, hmmmmm.

tyvm Dennis.