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    • CommentAuthorEd Davies
    • CommentTimeJun 5th 2014
     
    Am I right in remembering that the term “WBP ply” has been superseded? If so, what's the new magic incantation?
    • CommentAuthorBeau
    • CommentTimeJun 5th 2014
     
    There was talk about this in an old thread

    http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=11203&page=1#Item_6

    I can't access the Trada information but maybe you can.
    • CommentAuthorCWatters
    • CommentTimeJun 5th 2014 edited
     
    Google suggests that "WBP" was replaced with plywood made to EN 636 and EN 314. I think one covers the wood and the other the properties of the glue ???

    Perhaps see

    http://www.cfa.org.uk/userfiles/files/Guidance%20Note%20-%20Plywood%20-%20v1%20-%20July%202013.pdfand

    and this from 2008..

    http://www.tradewood.co.uk/media/c345d690feca47abb74ee560931b1ecbPlywood%20Standards.pdf

    "Recently, there have been some fundamental changes in the terminology used when specifying Plywood. There are two standards, one looks specifically at the wood species and one at the glue line as to how the Plywood performs, the two should be considered together."

    Continues..
    • CommentAuthorCWatters
    • CommentTimeJun 5th 2014
     
    PS:

    Asking for WBP was no guarantee you would get good quality waterproof plywood. Some of it wouldn't last a week outdoors.

    Structural Plywood is also something else.
    • CommentAuthorowlman
    • CommentTimeJun 5th 2014
     
    Posted By: CWatters</cite>PS:

    Asking for WBP was no guarantee you would get good quality waterproof plywood.


    That's right CW; The original WBP standard referred to the glue used in the construction and not the timber species AFAIK. That's probably the reason behind the updating of the terminology.
    • CommentAuthorEd Davies
    • CommentTimeJun 5th 2014
     
    Posted By: CWattersAsking for WBP was no guarantee you would get good quality waterproof plywood. Some of it wouldn't last a week outdoors.
    Ta. Bit ironic when it's supposed to be “weather proof”.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 6th 2014 edited
     
    Posted By: Ed DaviesBit ironic when it's supposed to be “weather proof”.
    Isn't it Water and Boil Proof rather than Weather and Boil Proof.

    Was studying the difference between weathering and erosion yesterday.:cool:
    • CommentAuthorborpin
    • CommentTimeJun 6th 2014
     
    Best to just go for some Marine Ply. I got some Ply that was supposedly to be to the top spec and some of it delaminated in weeks. By then it was on as window boxes.

    If you do, put some sadolins on every edge at least, before fitting.
    • CommentAuthorTimber
    • CommentTimeJun 6th 2014 edited
     
    WBP has been superceeded.

    The current standard is EN 636

    You get 3 classes...

    EN 636-1 which is for dry internal use
    EN 636-2 which is for internal humid (e.g. wall sheathing etc)
    EN 636-3 which is for exterior above ground use.

    A quality exterior grade ply should not delaminate after a few weeks, so I suggest that the stuff you bought was rubbish.

    Genuine Marine plywood only differs from exterior grade plywood in the the timber used in its construction - e.g. Marine plywood uses slightly or moderately durable timber in its construction, where as other grades of plywood make no requirements on species used. Proper marine plywood SHOULD cost an arm and a leg.

    Sealing edges with some form of end grain sealant will help prolong the life of the plywood, but should not be necessary.

    Also be warned that a hell of a lot of plywood is not actually structural!
  1.  
    Hay Timber, you're the man for wood knowledge :whorship:
    fancy explaining the different grades of OSB ? ( or a link )
    cheers
    • CommentAuthorEd Davies
    • CommentTimeJun 6th 2014
     
    Posted By: SteamyTeaIsn't it Water and Boil Proof rather than Weather and Boil Proof.
    That's what I thought but one of the references given here or on the other referenced thread said “weather”.
    • CommentAuthorTimber
    • CommentTimeJun 6th 2014
     
    It is weather and boil proof

    as for OSB, you have grades 1 to 4

    OSB/1 is non load bearing for dry conditions
    OSB/2 is load bearing for dry conditions
    OSB/3 is load bearing for humid conditions (i.e. Service class/hazard class 2)
    OSB/4 is heavy duty load bearing for humid conditions.

    There are no grades of OSB which are suitable for 'Exterior use' i.e. hazard class 3 (EN 636-3 plywood IS suitable for hazard class 3).
    • CommentAuthorwoodgnome
    • CommentTimeJun 6th 2014
     
    Just checked and my "WBP" Is in fact EN 636 -2.
    Both local builders merchants stock the same.
    Using it for Denby Dale type window boxes. Hope its ok. Sealing edges and might prime before fitting.
    • CommentAuthorTimber
    • CommentTimeJun 6th 2014
     
    <blockquote><cite>Posted By: woodgnome</cite>Just checked and my "WBP" Is in fact EN 636 -2.
    Both local builders merchants stock the same.
    Using it for Denby Dale type window boxes. Hope its ok. Sealing edges and might prime before fitting.</blockquote>

    Should be OK as long as you are not expecting to get directly wetted in service. Sealing edges will help.

    And CLASSIC situation there buying 'WBP' plywood with a certain expectation and then being sold something completely different.
    • CommentAuthorborpin
    • CommentTimeJun 6th 2014
     
    Posted By: TimberA quality exterior grade ply should not delaminate after a few weeks, so I suggest that the stuff you bought was rubbish.
    Yes it was but discovered too late. Built up boxes around widows. Installed boxed windows. Rail = delamination (in places). Far too late to strip out so treated immediately with sadolins and it seemed to stop the rot (so to speak!). Now encased so should not be getting wet again. It was class 3 'malayan' ply :(
    • CommentAuthorTriassic
    • CommentTimeJun 7th 2014
     
    Why is it I get a feeling that this whole ply, osb grade thing is a bit woolly, with cheap stuff masquerading as quality stuff.

    I'm sure most of it is a misunderstanding and no one is being ripped off.:confused:
    • CommentAuthorTimber
    • CommentTimeJun 7th 2014
     
    No 'cheap' osb on the market yet, and most of it is made in the UK using UK timber. With OSB you will get what you expect.

    Most the plywood we use in the UK comes from Europe or far east. No plywood is made in the UK. There is so much 'cheep' plywood around being sold as exterior grade that it is hard not to get ripped off!!!!

    For most construction applications OSB3 is a great choice
    • CommentAuthorTriassic
    • CommentTimeJun 7th 2014
     
    TIMBER, thanks,

    It's good to hear that OSB is untainted and we can buy with confidence.
  2.  
    anyone used tricoya?
    http://www.meditetricoya.com/
    • CommentAuthorTimber
    • CommentTimeJun 9th 2014
     
    Tricoya is really good stuff, but does cost a bit. The price is similar all-be-it a bit higher than genuine marine grade plywood, but in theory, Tricoya is more durable (in terms of decay) than light or standard grades of marine ply.
    • CommentAuthorEd Davies
    • CommentTimeJun 9th 2014
     
    Somebody whispered me some comments. This reference seems more generally useful:

    http://www.tbrewer.co.uk/sheet-materials/guide-to-constructional-plywood-a-osb

    Note the addition of 'S' or 'G' for structural or general.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 10th 2014
     
    Posted By: TimberTricoya is really good stuff,
    The bit I plopped in a bucket for 13 months did not seem to have suffered any degradation. Nice to work with as well.
    • CommentAuthorEd Davies
    • CommentTimeJun 10th 2014
     
    Then there's Q-Mark:

    http://www.bmtrada.co.uk/news/article/bm-trada-launches-marine-plywood-q-mark-scheme

    Seems to be FSC EN636-3 S marine ply. So why does one supplier do Q-mark 18 mm sheets for £34.80 but “marine WBP” for £56.10? All a bit of a puzzle.
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