plywood grades, the in's and out's guide

Discussion in 'Subfloor Preparation' started by Matt, Mar 11, 2012.

  1. Matt

    Matt Well-Known Member Staff Member

    6,342
    1,402
    113
    Plywood Grades:

    When buying plywood at your local supplier, you may notice that there are a number of different grades. The normal grading system uses the letters A, B, C & D, where A is the best quality, with virtually no blemishes and very well sanded. Grade D typically contains up to the maximum number of blemishes allowed.
    The letter grades typically come in pairs, where one letter refers to the "better" side, called the face, and the other letter to the back side, opposite the face. As such, a sheet of A-C plywood will be very well finished on the face with a relatively unfinished back. Conversely, construction grade plywood would be C-D (commonly referred to as CDX plywood), which is great for structural use but not suited to be finish material.

    Plywood Bonding Types:


    In addition to the plywood grades, there are four common plywood bonding types. The difference is in the glues that are used to bind the plies, or layers of the plywood.

    Interior Plywood:

    Plywoods for interior use only are made from various hardwood and softwood species, and can be used only in interior applications such as wall sheathing, furniture (where exposure to moisture is limited), cabinetry and the like. Interior plywood is available in most grades, as well as a number of hardwood species such as birch, oak and cherry. Interior plywood is dried and constructed for internal conditions

    Exterior Plywood:

    The most common type of plywood, readily available at home centers. The glues used in exterior plywoods are much more resistant to moisture than interior plywoods. Once again, nearly all grades are available, with A-C, B-C and CDX the most common. Numerous hardwood species are also available in exterior varieties. Exterior plywood is dried and constructed for external conditions,YES dried for exterior use

    Marine Plywood:


    When moisture resistance is a priority, look into marine plywood. This type uses the best adhesives and is manufactured to the highest standards. It also is most commonly graded as A-A, with two top grade faces, but is limited in the hardwood choices that are practical for use in marine settings. Marine is dried similar to Exterior plywood. It is designed for marine use

    Structural Plywood:

    When the appearance of the face is of lesser concern than the strength and stability of the material, structural plywood will typically be the choice. The resins used to adhere the plies are designed for extra strength to avoid separating of the layers. Structural plywood is seldom found in a grade higher than C-D. It is commonly used in concrete forms on
     
  2. dazlight

    dazlight Super Moderator

    7,017
    1,658
    113
    Good guide that Matt.
    So what is best out of above?
    I need to order 25 sheets this week for a Nursery job.
     
  3. Matt

    Matt Well-Known Member Staff Member

    6,342
    1,402
    113

    DAZ, where is the plywood going to be installed? internal? so the correct plywood would be Internal! BUT with the crap we are being sold installers are using all types.

    Like i say we should be installing internal........
     
  4. tarkett85

    tarkett85 Well-Known Member

    3,172
    483
    83
    What are you fitting? If they'll pay for it go for Marine ply by far the most stable.
     
  5. dazlight

    dazlight Super Moderator

    7,017
    1,658
    113
    Marley safetred spectrum. And carpet tiles.
    I have used some from Travis Perkins last week so going to get that.
    It's far eastern hardwood WBP, seams good gear. It has a stamp on it so will take a picture when I use it.
     
  6. brenchy

    brenchy Well-Known Member

    127
    41
    28
    Surely by using ply like a Spruce ply that conform to BS5268 you should have no problems. I have alot of experience in plywood and most of that plys that flood the builders yards are cheap chinese with veneers so bloody thin you dare not bond anything to it.

    Try where poss purchase ply which has the TRADA mark or WISA spruce and with a WBP glue line this will provide you with ply that has been load tested, and is bonded together with an external phenol formaldehyde and is the same thickness throught the whole pack...... :D
     
  7. dazlight

    dazlight Super Moderator

    7,017
    1,658
    113
    Where would you get that mate?
     
  8. brenchy

    brenchy Well-Known Member

    127
    41
    28
    Mate any good timber merchant: Lathams , travis, jewsons, EH smith just need to ask for the right gear. :D
     
  9. Spacey

    Spacey Super Moderator Staff Member

    6,516
    1,881
    113
    If you don't ask what ply your local sellers are giving you they will give you any old rubbish & the grade can vary at the same place week to week. I normally ask to see it to check it every time & they still give me the same comments "But its only plywood mate!"
     
  10. merit

    merit Well-Known Member

    8,131
    1,651
    113
    You shouldn't have to ask tho! Of I'm buying plywood from a flooring wholesaler I would expect it to be suitable to lay flooring on! If its not they are taking the ****!
     
  11. dazza

    dazza Well-Known Member

    698
    103
    43
    But the floor fails surely its down to the flooring wholesaler ?
     
  12. mjfl

    mjfl Well-Known Member

    6,263
    1,594
    113
    So, you buy it because the wholesaler should know if it's good, but where does he buy it from and is he told it's suitable? he's only the middle man, I agree that he should sell the best quality for flooring but until it's stamped quality flooring grade then this will continue...
    If you buy any other goods tv,washing machine,van the person selling it will always tell you it's good quality for the money, when it breaks what happens, they tell you to contact the manufacturer except van ofcourse...
     
  13. Dave Hearn

    Dave Hearn Active Member

    28
    0
    1
    Try to steer clear of b and q ply I once did an amtico job on top of customer supplied bnq ply and it had gaps in the middle layer and stilettos went straight through. I use wbp flooring grade ply which is stocked by carpet and flooring headlam/Garrard waters.
     
  14. merit

    merit Well-Known Member

    8,131
    1,651
    113
    Last bit of b and a ply I used looked more like a quaver than a sheet of ply. Awful


    Sent from my iPhone using Tapatalk
     
  15. Rugmunching

    Rugmunching Well-Known Member

    3,776
    651
    113
    Try explaining to a customer you can't use mdf board :confused:

    B&Q ply.....say no more.....
     
  16. Dave Hearn

    Dave Hearn Active Member

    28
    0
    1
    ΔΆ
    We could always go back to oil tempered hardboard? Yak
     
  17. Spacey

    Spacey Super Moderator Staff Member

    6,516
    1,881
    113
    This Thread is now irrelevant

    The only flooring grade ply woods are SP101 or FG1
     
  18. Spacey

    Spacey Super Moderator Staff Member

    6,516
    1,881
    113
    Or birch wood
     
  19. Rugmunching

    Rugmunching Well-Known Member

    3,776
    651
    113
    Or 18mm mdf as 1 of my customers tried to convince me with :D
     
  20. Spacey

    Spacey Super Moderator Staff Member

    6,516
    1,881
    113
    9mm ???
     

Share This Page