Under siding--OSB vs Ply?

Discussion in 'Roofing and Siding' started by TaskBoy, Sep 8, 2008.

  1. Sep 8, 2008 #1

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    I want to install a sheet under the Hardiplank siding--which is better OSB or Etx. Ply? What about cost diff? Thanks.
     
  2. Sep 8, 2008 #2

    kok328

    kok328

    kok328

    Well-Known Member

    Joined:
    Nov 20, 2007
    Messages:
    2,755
    Likes Received:
    249
    OSB will be more affordable and is pretty much what all the new builds are made w/.
     
  3. Sep 10, 2008 #3

    glennjanie

    glennjanie

    glennjanie

    Well-Known Member

    Joined:
    Mar 1, 2006
    Messages:
    2,990
    Likes Received:
    4
    Hello TaskBoy:
    OSB is more eco-friendly too because it uses all of the log; there are no slabs cut off. I recommend it for the green effect.
    Glenn
     
  4. Sep 10, 2008 #4

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    Hi Glenn, thanks for the green info. We are into supporting that if finances allow. Sounds like a good choice for us.
     
  5. Sep 10, 2008 #5

    handyguys

    handyguys

    handyguys

    Well-Known Member

    Joined:
    Feb 22, 2008
    Messages:
    815
    Likes Received:
    2
    OSB is OK but plywood is the more premium quality product in my opinion. Take a heavy hammer to a piece of OSB sheathing and you can easily punch a hole, not possible with plywood. OSB can also suck up water much more easily if it gets wet, especially at the edges. This is most pronounced under roof shingles. A swollen board wont cause a a big issue with hardiplank.

    see
    http://www.inspectorsjournal.com/forum/uploads/Erby/2007112452818_DSC03531.JPG
    http://www.rd.com/familyhandyman/content/19557/
    http://www.extremehowto.com/xh/graphics/articles/art_60280_rightrooflead.jpg

    Trees do grow back and plywood is generally made from a fast growing tree crop planted especially for wood products after harvesting. OSB is generally cheaper than ply.
     
  6. Sep 11, 2008 #6

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    One contractor I talked to today said he was going to go right on the studs with two layers of waterproof membrane under. Hardie's install sheet says you can go onto studs or onto 7/16 OSB--what would you folks recommend? Thanks.
     
  7. Sep 11, 2008 #7

    handyguys

    handyguys

    handyguys

    Well-Known Member

    Joined:
    Feb 22, 2008
    Messages:
    815
    Likes Received:
    2
    Last time I did hardieboard I did

    Studs - 1/2" OSB - Tyvek - tape seams - Hardieboard

    The stuff is rigid but not that rigid IMO.
     
  8. Sep 13, 2008 #8

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    I wanted to keep this related issue under the same thread...

    If I put sheathing under the Hardieplank like OSB or ply, does the additional thickness now mess up french door mounting position or the measurements of the doors I'm to order/install. Or do I just get std. dimension (frame thickness) ones? Sorry but I am not familiar with how doors are installed (yet). What about the existing vinyl windows--will the siding stick out too far with sheath under? Thanks!
     
  9. Sep 15, 2008 #9

    handyguys

    handyguys

    handyguys

    Well-Known Member

    Joined:
    Feb 22, 2008
    Messages:
    815
    Likes Received:
    2
    No issues - The doors will install after the OSB and before the siding. I would think you would be messed up on any jambs on the inside without the OSB.
     
  10. Sep 16, 2008 #10

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    Thanks. What about existing vinyl windows with adding OSB or even just leaving the existing ply siding in place--too thick then?
     
  11. Sep 16, 2008 #11

    handyguys

    handyguys

    handyguys

    Well-Known Member

    Joined:
    Feb 22, 2008
    Messages:
    815
    Likes Received:
    2
    Existing ply siding? Dunno. Depends how it was installed and how the windows were installed. If windows were set right to framing then plywood I can see why the guy proposing Hardi wants to do the same. Resetting the windows could be a lot of work. How old are the windows? Maybe this is a good time to replace the windows. Unfortunately this will effect trim and jambs inside. It may be possible to extend the jambs outside but I cant say for sure.
     
  12. Sep 17, 2008 #12

    TaskBoy

    TaskBoy

    TaskBoy

    Well-Known Member

    Joined:
    May 13, 2008
    Messages:
    139
    Likes Received:
    0
    I got clarification from a siding-only contractor--old siding is bye-bye, so no prob with hardie sticking out too far.
     
  13. Feb 16, 2009 #13

    GreenIsGood

    GreenIsGood

    GreenIsGood

    Howdy Ya'll!

    Joined:
    Feb 16, 2009
    Messages:
    29
    Likes Received:
    0
    In Montana 7/16" OSB is more afordable - about $9.00 a sheet Feb 2009 price. Plywood 7/16 is running $19.00 a sheet.

    We put OSB under our siding and had no issues with it. The fact that it's more eco-friendly is what made our decision a no brainer. The lower price was icing on the cake. I wish all 'going green' choices were more affordable.....but that is not the case.
     

Share This Page