flashing for vent roof penetrations

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by jwray, Nov 11, 2005.

  1. jwray

    jwray New Member

    Messages:
    96
    Location:
    Virginia
    I'm about to finish my DWV install by taking the vents through the roof. I have purchased some Oatey plastic roof jacks w/ a rubber/neoprene boot that goes around the pipe.

    Are there any secrets/tricks to:
    1. cutting the hole through the roof (I'm assuming I want the hole as small as possible w/minimum impact to the shingles?
    2. attaching the roof jack?
    3. getting the roof jack layered under the shingles (do I just stick the top under the shingle above the vent and lay the sides and bottom over the shingles?)
    4. sealing the roof jack at sides,bottom, top, fastener penetrations?
    5. sealing the roof jack around the pipe?

    Thanks,

    Joel
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    That's the general idea. Remember that the hole needs to be oval shaped, not round. Always follow the basic principle that flashing must overlap in the downhill direction. It is always the flashing that makes something waterproof. The Henry's is just for backup.
  3. jwray

    jwray New Member

    Messages:
    96
    Location:
    Virginia
    flashing specifics

    Jimbo,

    Thanks for the reply. I saw somewhere you can cut a piece of scrap pipe at the angle of the roof to use as a template for the hole.

    What do you mean be Henry?

    Should I put a couple of roofing nails in the top corners of the roof jack an leave the sides and bottom alone or nail there as well?

    Do I put roof sealant under the top and side edges (and of course over any exposed nail heads)?

    Silicone around the pipe/boot juncture?

    Thanks,

    Joel
  4. sulconst2

    sulconst2 New Member

    Messages:
    205
    Location:
    old bridge nj
    say if you are shingleing a new roof. get the top of the finished part of the shingle up to the bottom of pipe. install boot. nail were the nails will be covered. continue with shingle. if the boot doesnt lay nice throw nails in the corners of exposed area. boots are called "no caulk" so you dont need any sealant unless you want. if you use tar. have a rag dipped in thinner to smooth. one trick is to oversize the hole and use the boot to level the pipe. nothing worse than a pipe thru the roof on an angle! use regular roof nails and no sealant at pipe.
  5. jwray

    jwray New Member

    Messages:
    96
    Location:
    Virginia
    Just want to make sure I understand

    Sulconst2,

    Unfortunately I'm not doing the roof right now, so have to deal with "after the fact" on that.

    So if I understand correctly:

    I don't need to use any roof sealant (unless it will help me sleep better :) ) where the boot meets the shingles. I'm also assuming any exposed nail heads need some sealant.

    I only need a couple of nails along the top of the boot (preferrably to be covered by the shingle above if possible without damaging the existing shingle).

    Nice trick on oversizing the hole a bit to get the pipe plumb! Thanks.
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Henry's is just a brand of roof coatings. A good roofing supply house will advise you on the best products to use.
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