Replies

1. 
   Piffin | Apr 07, 2003 01:48am | #1

   Frenchy,

   Glad to help out, tho I hesitate to come between you and your boss on this.

   First thing is that whenever you have two differing pitches, you always, IMO, want a 'W' valley. It is broke at a sheet metal shop to give you a standing diverter in the center of the valley. See the attachment.

   Reason is that when you have one side steeper or gaining more volumn of water, the flow will not be centered and can back up under the opposite side of the valley. The diverter will break the force of the water and give you a straight looking job.

   The other thing to consider when sizing a valley is the type shiungles you are using. They will have some influencer on how close you can nail to the center of the valley. One hard and fast rule is that you never drive a nail or staple into the valley metal. If you do that, there's no sense in using meatl valleys because you just poked it fuill of holes. So if the closet yopu can nail wioth a certain kind of shingle is ten inches, then there is no need for a valley to be designed any wider than twenty inches since you would have to poke nails into it to install the shingles.

   You back it up with ice and water shield and use the returns you can see in the attachment and you'll be fine with a sixteen inch valley, for most jobs. The attached photo is of a twenty inch valley which took 24" of metal to break. It was for a Cedar shake roof with low pitch.

   .

   Excellence is its own reward!

   
1. 
   RussellAssoc | Apr 07, 2003 03:41pm | #3

      Also note he is using a return at each outside edge, another quality detail.  This return should not be completely bent down, it should have the spring effect of the old bronze door weather strip.  Another detail is to expand the width of the exposed valley flashing 1" to 2"  on each side from top to bottom to allow for the additional accumulation of water as it approachs the gutter.  Good luck, hope you don't get arrested.

1. 
   fdampier5 | Apr 07, 2003 06:14pm | #7

   Good note,  do you think using copper that is at least three times as thick as typical flashing will change anything?  (other than having to prepunch nailing holes..)   what nailing schedule should I use?

1. 
   Stray | Apr 07, 2003 06:55pm | #8

   The return on the edges is also used in fastening the metal via copper clips.  Nailing directly throught the valley flashing won't let the metal expand and contract.  This is especially true in long runs.  The clips allow the metal to expand up/down the legnth.  Otherwise the metal will, over time, enlarge the nail holes ands loosten up on ya.

1. 
   fdampier5 | Apr 07, 2003 07:02pm | #9

   ok good point, but how will clips keep it in place?  I assume that you use clips of the same copper and I would think that clips made of copper would not really have the needed spring to hold the copper firmly in place.  Or do you use clips on the side and nail the copper at the bottom? 

2. 
   RussellAssoc | Apr 07, 2003 08:53pm | #10

           We generally use copper with slate or shakes.  It's actually not recommended with shakes because of natural oils, however, it still lasts forever in practical application.  1st set the flashing in an ice & watershield bed extending 6" or more outside the flashing edge. The best way to nail is to use copper nails through tabs hooked over the 1" spring fin nailed through the valley ice & watershield bed, thus avoiding piercing the flashing.  Nail shakes, slate, shingles up to but not through the copper flashing edge if possible.  The roofing nailed just up to the edge will apply enough pressure for the shingle to depress the spring fin, the return edge I mentioned in my previous post, running along the flashing edge to provide a water tight valley.  In another not quite as good application, you can forget the tabs and fasten the flashing to the valley with copper nails driven, sparingly, close to the flashing edge.  These nails must be driven through ice & watershield, not just into the decking.  If you absolutely must, you can also drive copper nails through the shingle, flashing, and ice & watershield near the flashing edge.  Good luck.

      Remember if you have a roofing card your good to perform any trade.

2. 
   fdampier5 | Apr 07, 2003 06:11pm | #6

   Thanks Piffan,

    that's exactly why I like this site so much.  people like yourself willing to help some dumb carpenter wanna-be.  I'll be sure to tell frenchy to send you a note of thanks..

1. 
   Piffin | Apr 08, 2003 06:58am | #11

   It is a great site, full of great people.

   Here's how I install that kind of flashing.

   I run a chaulk line down the center after applying the ice/wate shield. The flashing is made up in ten foot lengths. I place it in the valley and line up the center W #### on the chaulk line. With your steep pitch, you'l jhave to figure out the best way to line things up according to your equipment and body english ( or french, as the case may be).

   I nail through the copper at the very top of the ten foot length and let it hangf and then align the bottom to the center mark - or with the second piece, it falls into place.

   Then I don't bother with clips. I use a copper roofing nail set right at the edge of the folded return and the head of the nail then pinches down on the flashing enough to keep it aligned when I have one on each side about every two or three feet. The nail at the top end keeps it from sliding down and thermal expansion will still be possible..

   Excellence is its own reward!

1. 
   fdampier5 | Apr 08, 2003 05:31pm | #12

   thanks,  that sounds like a very workable plan..  since I'll be bending this up on a sheet metal brake myself, I probably won't be able to put the spring edge that they speak on in it..  Besides  as thick as the copper is I believe that it would have a definate lump If I were to fold it over as they show on the earlier example.

     One nice thing, as thick as this flashing is it will take three forevers to wear out..<G>

1. 
   GoldenWreckedAngle | Apr 08, 2003 07:32pm | #13

   Frenchy, do you ever get tired of overkilling things. You strike me as the kind of guy who would try to rid yourself of a rodent with a rocket launcher.

   Just what are you trying to compensate for - or is that a whole nother flashing issue? :-)>

   Sorry man- I'll try to aim a little higher with my jabs in the future. You were just so wide open on that one I had to take the shot.Kevin Halliburton

   "One machine can do the work of fifty ordinary men. No machine can do the work of one extraordinary man." -Elbert Hubbard-

2. 
   BossHog | Apr 08, 2003 08:21pm | #14

   While we're throwing around low-rent insults -

   How come you didn't CALL me this morning like you said you would ???

   Guess I shouldn't expect an ARCHITECT to do what they said they were gonna do...........................(-:

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   .

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   (Hey - YOU started it)My Wife asked me how long I was going to be gone on this business trip. I said, "the whole time."

3. 
   GoldenWreckedAngle | Apr 08, 2003 08:56pm | #15

   You just can't "truss" anybody now can you Boss? I assure you I kept my word. You should have heard all the stuff I was calling you this morning.

   Sorry, I got a little side tracked but I haven't forgotten ya. Typing with one hand and dialing with the other...

   Be talking to you uno momento.Kevin Halliburton

   "One machine can do the work of fifty ordinary men. No machine can do the work of one extraordinary man." -Elbert Hubbard-

4. 
   fdampier5 | Apr 09, 2003 02:25am | #16

   It's my cheapskate nature..  I found a deal on some copper and so what if it was a little thick,  OK, a lot thick..

    As for riding myself of a mouse with a rocket launcher how silly,   however if you have a deal on a lion we can talk..

      As for compensation,  ....Nah, I won't go there, way too big a subject to discuss on this board.    <G>

2. 
   Piffin | Apr 07, 2003 01:49am | #2

   Now be flashed -

   pervert indeed!

   .

   Excellence is its own reward!

3. 
   BossHog | Apr 07, 2003 03:52pm | #4

   "and there is a pretty good arguement raging.. "

   Argueing with the boss ???

   Karaoke bars combine two of the nation's greatest evils - people who shouldn't drink with people who shouldn't sing.

1. 
   fdampier5 | Apr 07, 2003 06:07pm | #5

   You know frenchy, he's highly opinionated and prone to arguements.. In fact he should be fired, but that's another post....;-)