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roofover flashing question

hammer102 | Posted in Construction Techniques on March 11, 2009 12:39pm

I have a roof to exterior wall roofover flashing question.  The existing step flashing and asphault shingles are in decent shape.  Just doing a roofover.  The siding is aluminum, and I am unable to budge the j channel that lays on the existing shingles.  I would like to install new step flashing, but the siding does not budge and I don’t see me getting the flashing behind the siding , without removing a whole walls worth of aluminum siding.  Most of the new shingles (timberline) will not even fit under the j channel, as it is installed very tight down to the roof.   So, my question is can I get away with butting the new shingles to the j channel, since the roof/wall intersection is already flashed?

PS- This job is already complete.  I got a couple shingles under the J, but most not.  No new step flashing.  There are multiple peices of J channel, and the seams are lapped over, for propper drainage.  I also used Flashmate, its  a caulking for flashing, says its guaranteed for 50 years on the tube, where the shingles meet the J channel.  I’ve been water tight for 1 year.  Any one see this failing?  A neighbor with the same house wants there roof done, but the J channel on their roof is not lapped properly for drainage, the peices are just but togeather, making a way water could get in.  Many neighboring houses have been done and no one has removed the aluminum siding to re-flash.

I could cut away the existing shingles that are at the intersection, and install the new shingles to the existing step flashing, but then the shingles would be pitched towards the wall 2 layers to one by the wall, diverting water toward the house, which I don’t like.

I know this situation is common to seasoned roofers.  I have just a few new construction roofs, and roofovers without this situation, under my belt and need some advice.  Thanks- Chuck


Edited 3/11/2009 5:49 am ET by hammer102

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  1. theslateman | Mar 11, 2009 12:58pm | #1

    You probably know that in that situation the best method would be to strip the entire roof - not just 2' wide at the house juncture.

    1. hammer102 | Mar 11, 2009 01:07pm | #2

      Yeah, I know tear off is best.  But it's not what happened/ will happen.  So, I should have/should in the future cut back a few inches and install new shingle to the old step flashing?

  2. seeyou | Mar 11, 2009 01:13pm | #3

    Catefully take the siding off of the dormers, flash correctly, then re-install the siding.

    http://www.quittintime.com/      View Image        

    1. cic317 | Mar 11, 2009 03:56pm | #4

      Make life easy, Present a price for either option to homeowner w/ your recommendation & let them decide . then you off the hook, & still make a profit

      1. seeyou | Mar 11, 2009 04:20pm | #6

        Make life easy, Present a price for either option to homeowner w/ your recommendation & let them decide . then you off the hook, & still make a profit

         

         

        I've done that a time or two and it's always come back to bite me in the butt. Do it right or walk away. Doesn't matter if you gave them two options. If it leaks, they won't tell everybody about them being a cheapskate. They'll just tell everyone that will listen that their new roof leaks. http://www.quittintime.com/      View Image        

  3. gzajac | Mar 11, 2009 04:13pm | #5

    Hammer

    I do repairs on items like this frequently. Last one involved a dormer with twenty foot sides with a roof over. Roofing crew roofed to existing Texture 1-11 than sealed the joint with a hideous 2" swath of roofing cement.

    Dormer leaked for the next three years, three different ROOFING contractors came in and added tar, but never fixed issue.I came in removed tar, removed texture 1-11 and reflashed, problem solved.

    In the three years time, the sheetrock ceiling, majority of fiberglass insulation, and sheetrock and trim around windows deteriorated badly , and had to be replaced. They repairs were expensive, but they are trying to get reimbursed by the original roofing contractor, going back five years.

    My advice if you can't do it right, don't bother doing it, it will only came back to bite you in the a**.

    Greg in Connecticut

    1. seeyou | Mar 11, 2009 04:22pm | #7

      it will only came back to bite you in the a**.

      deja vu.

      Hey, not to hijack this thread, but are you still up for the Flaming Winnebago of Death?http://www.quittintime.com/      View Image        

    2. hammer102 | Mar 13, 2009 01:23am | #8

      I am leaning towards removing the shingles against the intersection to the house and findingh some way to get some step flashing behind the aluminum siding.  It's not leaking and it probably never will, but I know I did it wrong, and the flashing cement  or the j channel could potentially fail.  This is the house I live in, and I could do it in one day.  I don't know.  I had wrote it off until a neighbor sent me up on their roof to face the scenario all over again.  I wouldn't feel confortable doing it the same way over again on their house.  Maybe I will get up there and take pictures and change it. 

      I think I will trim the step flashing so there is an inch or more that will fit behind the j channel before I run into a nail.  I guess I would use a pry bar to jack up the aluminum j a little so I could get the flashing and a shingle under there.

      You know, while I was doing it, I wrote it off saying "I know there is already flashing back there, reflashing it is overkill".  Now I can't let it go.  Would have been much easier to do it right the first time.  It will be better still to do it now before a leak occurs, than to have to replace sheathing and sheetrock.  Oh, bother.

      Besides that, I did not reflash the two 9' long valleys on the roof.  Didn't see the point.  Now that I read some articles on this site, I see that reflashing the valleys on a roof over is highly recomended.  Son of a b*****.  I just don't see the valley failing before it is time to tear the whole roof off and start over in 30 years.  And if it ever did, there is the original flashing under the 1st course of shingles, so I am not going to rip up the whole valley to put in redundant flashing, though I cleary see the benefit.

      Im frustrated because I didn't research enough to make up for the experience I didn't have when I did this roof in the first place.  Now I see how easily I could have made the roof bulletproof, and got some peace of mind.  Oh well, at 27, only 8 years in the trade, still wet behind the ears!

  4. User avater
    Dinosaur | Mar 13, 2009 02:27am | #9

    Doing it half-arsed for yourself, and doing it half-arsed for someone else are two different situations. You aren't going to sue yourself if it leaks; your neighbour might very well do so if it all turns to merde after you're done and his gyprock, insulation, and framing get wet and nasty.

    Pulling the bottom course or two of siding to flash properly is a PITA, but it is eminently doable. Like the sneaker ads say, Just Do It.

    Dinosaur

    How now, Mighty Sauron, that thou art not brought
    low by this? For thine evil pales before that which
    foolish men call Justice....

  5. muffy1 | Mar 13, 2009 02:39pm | #10

    Smack chalk line apx 2" above roof--Fine tooth blade in circular saw--Cut siding  and remove siding and J channel. Silp step flashing behind siding---Slide new J ch. under siding for finish. I use hole puncher on outside of J  for water relief

    1. hammer102 | Mar 13, 2009 04:42pm | #11

      That is something that I really have not thought of at all.  That would certainly give me room to work, and to reflash.  Perhaps I could then get a color matched paint and paint the visible new step flashing to match the siding, or maybe just black or whatever color.  That would be the only house on the block done this way.  I really like that idea though.  I don't know if step flashing will fit back there without cutting back siding.  Nice to have another approach now!

      I am going to go talk to a neighbor I am friendly with who had his roof done by someone else and get up on his roof and see what they did, or didn't do, at the roof/wall intersections.

      By the way, this intersection is not at the peak on a shed type roof, it is at the end rafter of a gable type roof.   Might be confusing without pictures.

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