I live in the Seattle area and am re-siding my house with 1/2 x 6 beveled cedar siding. I recently had a post on installation and someone suggested that I might seal the step flashing on the roof to the sheathing with Vycor, starting about 1″ from the bottom of the flashing. The roof is about two years old. All agreed that this is a good idea? If so, what would be best: Ice and Water Shield, Tri-Flex 30, or Ultra? I’m not familiar with Vycor at all.
Also, the paper covering the sheathing is mostly asphalt felt(house was built in 1928)? Not sure of the weight, 30# or 15#? Should I continue with that, or can I get away with a plain paper wrap? Are there different varieties of paper?
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Maybe I suggested that. Vycor is a Grace product and should be available wherever you saw Ice and Water Shield. Vycor is relatively thin and is useful for a lot of flashing, although not directly on the roof deck. You can get 4", 6" 9" and 12" rolls x 75 feet long. It can be difficult to handle long pieces alone. If you fumble around with it and get the back stuck to itself... forget it, toss it, cut a new piece. We usually get it positioned where we want it, and then one guy holds the beginning down while the other peels the back out from behind it and presses it into place. After a few dozen rolls you get pretty good at it, but in the beginning you may waste some.
David,Yes, thanks for another post on this; I responded to your intial post(with more questions), but I didn't hear back from you. I'm a bit confused by PIFIN's post, however(see his reply to me in this thread). Not sure why he's suggesting that it's impossible to use the Vycor as you suggested? Hopefully, I can get him to elaborate. At any rate, I now have a good idea what you're talking about and what challenges I might face working with it.
You cannot seal step flashing to the roof. You can seal it to the sidewall if you want, after all the flashing and roofing is installed and before the felt is installed. I do that in some cases where there is a lot of wind-driven rain, such as on my own house which faces about 6000 miles of open water and gets blasting gusts of wind during winter storms. This is not something you NEED to do. Do not get the laps reversed as in the photo showing the tyvek building that someone else posted.
David,Thanks for clarifying; I do believe we're on the same page.
I know the San Juan Islands well and I know about wind-driven rain! Even up here in Lake Forest Park, WA, surrounded on all sides by tall Doug Fir, the wind during the winter can be intense (my main concern is always that one of those trees doesn't come crashing down onto the roof).Do you concur that I should only be using tarpaper for the underlayment? I've noticed that under the porch, a previous owner only used a thin black paper (not sure what it is).
"I might seal the step flashing on the roof to the sheathing"
Maybe you misunderstood. thye step flashing is to be woven in with each shingle. If it is sealed to the sheathing, that is imp[ossible. It would then be better to use straight base flashing and skip the idea of using stpe flashing.
As for the paper. You should know what it is, because you should be putting down new tarpaper underlayment. Fold it at the break to the dormer wall and make sure it runs up the wall at least eight incvhes with all laps facing downhill. Do that and you won't be needing any vycor there.
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PIFIN,Thanks for posting.First, the new roof is already on."The step flashing is to be woven in with each shingle."Yes, I understand that the step flashing is woven in to each shingle (on the roof). If I understand davidmelland's post, he's suggesting that I run a strip of Vycor OVER the top of all the step flashing as it sits flush with the sheathing (on the wall). Then, put the tarpaper underlayment over that. I realize this isn't standand practice, but I believe his suggestion was meant to afford me more protection than simply overlapping the step flashing with tarpaper underlayment? As for the underlayment that I staple onto the sheathing (on the roof), you are saying I should only be using tarpaper? What about the sheathing under the front porch where I know I won't have any water? Thanks for your feedback.
yeah, you weren't clear. fine to use vycor on wall for insuance if you want. under the porch? now you've lost me again
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