+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    Join Date
    Aug 2011
    Posts
    2

    Default cedar shakes cupping

    In late spring, I had 2 sides of my house stripped and new cedar shakes put up over new Tyvek (note: a 3rd side was replaced in 2005 and the front has a different product). I then had Rhinoshield paint applied a few weeks later. Rhinoshield was applied over an oil based primer.
    After today's tropical storm we were surveying the house and grounds. I found that on the 2 sides where new shingles were applied, 10-15% of those shingles are noticeably cupping. I don't know if this was due to the quality of the shingles, the install of the shingles or the Rhinoshield. The 3rd side does appear to have been affected.
    Any advice?
    Thank you!

  2. #2
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: cedar shakes cupping

    first question were the shingles installed directly on top of teh tyvek, reason i ask is that this is wrong the oils in the cedar will destroy the water proofing ability of the tyvek. its ok to use tyvek but there must be either cedar breather or privacy lattice installed on top of the tyvek first so to create a air space and to keep the cedar from being in contact with the tyvek

    as for teh shingles cupping its caused by irregular drying of them, the wood is drying faster on the face than on the back plus the installer nailed too high on them. if you need to drive some finish nails to draw them back down
    fire up the saw and make some dust

  3. #3
    Join Date
    Aug 2011
    Posts
    2

    Default Re: cedar shakes cupping

    The shingles are drying out and are now mostly flat again. I checked and he did install the shingles directly onto the tyvek. Should I make an issue of this with the installer? He is the same person who did the first side back in 2005, and did an excellent job. These 2 recent sides just don't look as good. Will they last?

  4. #4
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: cedar shakes cupping

    the cedar will last a bit but with the cedar directly on the tyvek... the tyvek wont last, if the water gets behind the cedar you will have leaks.. make sure you make the contractor aware of this, he can use tar paper but not tarpaper.. if hes gets ignorant about it he needs to hang up the tool belt . he'd be fired off my site instantly and get blacklisted. siding and weatherproofing are a big deal, you cant mess around with it
    fire up the saw and make some dust

  5. #5
    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    1,180

    Default Re: cedar shakes cupping

    I'm gonna guess it's partly due to the fact that the undersides of the shakes are not painted, therefore in wind-driven rains they get wet while the outside sealed for now with some superpaint remain dry. This could be avoided by ordering the shingles pre-dipped in stain, and could have been made less troublesome by laying them over a mesh rainscreen product. At this point there's nothing to be done but get used to the post-deluge warping.
    Casey
    Remove not the ancient landmark, which your fathers have set.

  6. #6
    Join Date
    Sep 2009
    Location
    florida
    Posts
    598

    Default Re: cedar shakes cupping

    Quote Originally Posted by jkirk View Post
    first question were the shingles installed directly on top of teh tyvek, reason i ask is that this is wrong the oils in the cedar will destroy the water proofing ability of the tyvek.

    JK,,,,,

    FAQ...Is DuPont™ Tyvek® a vapor barrier?

    No, DuPont™ Tyvek® is not a vapor barrier. It is breathable, allowing moisture vapor to pass through it.
    Gizmo

    Cut it 3 times & it's still to short.
    Inventor of the Miter Master Plus.

    Hidden Content
    Hidden Content

  7. #7
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: cedar shakes cupping

    Gizmo -- there's a differnce between water vapour and liquid water.
    House wrap doesn't allow liquid water to penetrate yet allows water vapour to pass through --- that's why it's considered an exterior weather barrier.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  8. #8
    Join Date
    Sep 2009
    Location
    florida
    Posts
    598

    Default Re: cedar shakes cupping

    Wood Siding
    DuPont™ Tyvek® weather barriers and wood siding shall be installed according to
    manufacturer’s instructions, industry standards and applicable codes. As recommended
    by the Western Red Cedar Lumber Association and U. S. Forest Product Laboratory,
    wood siding should be primed on all six sides before installation. In high exposure
    installations, enhanced drainage and water management may be provided by using
    DuPont™ Tyvek® CommercialWrap® D or by creating rainscreen cladding with a larger
    airspace behind the siding using furring strips.
    Gizmo

    Cut it 3 times & it's still to short.
    Inventor of the Miter Master Plus.

    Hidden Content
    Hidden Content

  9. #9
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: cedar shakes cupping

    dupont makes standard tyvek, and they make a version specific to wood siding which has the rain screen built into it. but its well documented that cedar should not be in direct contact with tyvek for the reason i stated. plus i have seen the results first hand

    unless there is a difference in the product sold in the states
    fire up the saw and make some dust

  10. #10
    Join Date
    Sep 2009
    Location
    florida
    Posts
    598

    Default Re: cedar shakes cupping

    I looked for any product/document/warnings from Tyvek, All I could find was DuPont™ Tyvek® weather barriers and wood siding shall be installed according to
    manufacturer’s instructions, industry standards and applicable codes. As recommended
    by the Western Red Cedar Lumber Association
    and U. S. Forest Product Laboratory

    http://www.wrcla.org/pdf/WRCLA_Installing_Siding.pdf

    Does the so called break down of the Tyvek have to do with the oils or Tanic Acid in the cedar ?
    Gizmo

    Cut it 3 times & it's still to short.
    Inventor of the Miter Master Plus.

    Hidden Content
    Hidden Content

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •