What is this?

Discussion in 'Flooring' started by scarymary, Apr 16, 2010.

  1. Apr 16, 2010 #1

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    Yesterday my brother decided to pull up a piece of the particle board in the living room, (which is a converted carport/garage) and found this underneath. The plan is to install laminate flooring over the entire floor including the stairs. Don't worry, I only have 3 steps down. My question is would I necessarily need to install a piece of thick moisture resistant plywood on top of this before laying the laminate or can I get by with something not quite as expensive or thick as 3/4 inch plywood, but just as durable and acceptable for putting down the laminate flooring? These planks run all the way over the room. Actually I fully expected to see just 2x4s laid flat underneath the particle board on top of the concrete, but not the case. It looks like cedar planks to me, but I could be wrong.

    subfloor.JPG
     
    Last edited: Apr 16, 2010
  2. Apr 16, 2010 #2

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    Those are fir 1X6's I think (judging by the wood grain pattern).

    If that is a converted carport/garage, then someone must have built a wood floor over the concrete garage pad (for a warmer floor). No one would have built a wood floor expecting to park a car on it.

    Before you cover that up, I would inspect the ends of the floorboards carefully to see if they've been cut. It doesn't look so from the photo. Those floor boards aren't perfectly flat, so anyone cutting through the particle board with a circular saw after it was installed would have left kerf marks in the particle board and would have scored the crests of the floor boards. It looks to me that the underlayment (the particle board) was just nailed down with a piece missing, and a small piece of particle board was put in to fill in that spot. Your brother pryed up that small piece.

    You can just nail down a new piece of particle board of the same thickness.

    But, if it were me, I would pull up ALL of that particle board and nail down plywood underlayment instead. The difference between plywood and plywood underlayment is that plywood is allowed to have voids in the inner plies. These voids would cause problems ("soft spots") on a floor, and so any voids in plywood underlayment have to be smaller than a certain size or filled with a filling material.

    The difference between plywood and particle board underlayment is that getting wet won't harm plywood underlayment. If particle board underlayment gets wet, it swells up and gets soft. They only used particle board as underlayment because it was cheap. Fir plywood underlayment is much more durable than particle board underlayment, and you wouldn't have to worry about any large water spills wrecking the underlayment.
     
    Last edited: Apr 16, 2010
  3. Apr 16, 2010 #3

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    Actually, the particle board covers all of that plank style that you see in the picture. There was carpet on top of that. We have removed all of the carpet. What I'm driving at here is would we necessarily need to put something of a thickness of 3/4" plywood or could we go with something thinner over the top of that plank that you see in the pic? Oh, and there are some type of joists underneath those planks there in the picture. They are nailed to something.
     
    Last edited: Apr 16, 2010
  4. Apr 16, 2010 #4

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    ScaryMary:

    Thinner. You should put the same thickness of material down over those planks as the piece you removed. That looks to be about 3/8 inch thickness approximately. So you would use whatever thickness of material that that you took out because that would result in the floor over the planks being flush and level with the surrounding floor.

    If someone told you that you need to nail down 3/4 inch plywood over those planks, they simply didn't understand the situation.

    You should understand that it's those planks that provide all the strength to your floor. The "underlayment" that you removed (and now need to replace) doesn't provide any strength. It's just there to provide a smooth surface over which to install the final flooring material.

    You don't need to know the rest:

    Normally when the build a house, they have floor joists which are supported by concrete walls of the house's basement. Over top of the floor joists they will nail down 1X6 plank or 3/4 inch fir plywood, and that layer of planks or plywood is called the "SUBFLOOR". Then the 2X6 exterior walls and 2X4 interior walls of the house are built on top of the subfloor. If the subfloor consists of planks, as it does in your case, the planks will be nailed down at an angle to the joists because doing so results in a more rigid construction than nailing them perpendicular to the joists.

    Then, they would normally nail down something called "UNDERLAYMENT" inside each "room" of the house to provide a smooth surface to install the flooring over. In your case, you have particle board underlayment.
    One of the benefits of installing plywood underlayment over a plywood subfloor (for example) is that if you ever want to remove flooring that is glued down, like sheet vinyl or carpet, you can pry the underlayment up with the flooring still glued to it, and then put down new underlayment to install the new flooring over. That would save a great deal of work trying to remove the old flooring.
     
    Last edited: Apr 16, 2010
  5. Apr 17, 2010 #5

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    This is a converted carport. There are joists under the planks there in the picture which are somehow, I am assuming, attached to the concrete floor of the previous carport/garage. The particle board we removed from the floor was 5/8". We measured it yesterday. We will probably remove the rest of the particle board today.
     
  6. Apr 17, 2010 #6

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    Replacing the particle board underlayment with plywood underlayment is a good idea. Particle board swells up and gets soft if it gets wet. The only reason particle board was used as an underlayment was because it was inexpensive. It's really not a good product to use for anything.

    Normally underlayment is meant to be thin, typically 3/8 inch in thickness or less. It's not necessary to use the same thickness of underlayment, but you may have to remove the baseboards from the walls and raise or lower them if you use a different thickness of underlayment. Riverside Wood Products here in Manitoba makes a 5/16 inch fir plywood underlayment which you can double up to make 5/8 of an inch.
     
  7. Apr 18, 2010 #7

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    My husband and I looked around at Lowes yesterday, but we didn't see any subfloor/underlayment material of 5/8" thickness. I wonder how much difference it would make to use something thicker than that.........
     
  8. Apr 18, 2010 #8

    Bud Cline

    Bud Cline

    Bud Cline

    Tile Contractor

    Joined:
    Apr 13, 2006
    Messages:
    284
    Likes Received:
    0
    The thicker the better. You are asking for trouble covering those boards when you could replace them with a more suitable plywood. Those boards will expand and contract and move around. Notice how some are cupped and some are crowned now. You wouldn't notice it under carpet but you will notice it under a hard surface flooring. You'll never keep the seams together in the finished flooring especially if you use one of those cheap "click" laminates that are being sold today.

    Get rid of those boards.

    Sorry Nestor but your research has yielded you some erroneous information.

    Underlayment plywood's are available in many thicknesses for various reasons. Underlayments ARE NOT meant to be thin, that is ridiculous.

    Remove those boards and use a 3/4" Exposure 1 "Underlayment" product and you'll be fine.

    And YES...the particle board was a mistake from the git-go.:)
     
  9. Apr 18, 2010 #9

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    I would never remove the plank subfloor to replace it with plywood.

    I would replace the particle board underlayment with fir plywood underlayment, and I would put that new underlayment over the plank subfloor.

    Scarymary:
    Take your picture down to any of the flooring stores in your area and ask to talk to the Installations Manager. In my view there's nothing wrong with your existing plank subfloor, and there is absolutely no reason to replace those planks with 3/4 inch plywood. Speak to the Installation Manager at several flooring stores and see if they agree that the subfloor needs to be replace. I very much doubt they would.
     
    Last edited: Apr 18, 2010
  10. Apr 18, 2010 #10

    Bud Cline

    Bud Cline

    Bud Cline

    Tile Contractor

    Joined:
    Apr 13, 2006
    Messages:
    284
    Likes Received:
    0
    Dimensional lumber in that form is unstable. It expands and contracts routinely to say nothing of the concaving and convexing going on with seasonal changes.

    The way to stabilize it is to cover it with plywood but even then the plywood install would be rickety rackety because of the condition of the boards. Now is the time to remedy any future problems.

    Seams in laminate flooring won't stay together when the substrate is changing form a couple of times per year. Get rid of that junk while the opportunity has presented itself. It will make good fire wood.:)
     
  11. Apr 18, 2010 #11

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    Bud:

    1X6 dimensional lumber will twist and warp as it dries IF IT IS FREE TO MOVE.

    In this case those boards were clamped in place by three (typically) nails per board to every joist. That held them in place as they dried, and prevented them from warping and twisting. Take a look at the picture. If those boards were warped, then you'd see gaps between the boards and the underlayment above. From what I can see, there are no such gaps and those board appear to be laying pretty darn flat to me.

    I have exactly the same kind of fir plank subfloor throughout my building, and my own experience is that the boards dry flat. Replacing those planks with plywood would be a waste of money.


    Mary:
    Just go to any carpet store and show your picture to the Installations Manager. He will confirm that your plank subfloor will not present any problems for the installation of any flooring you choose to install over it. He will also confirm that plywood underlayment would be better than the particle board underlayment you have now, but he may feel that it's not worth the cost to replace the underlayment. My own feeling is that now that the carpet is out, this would be the time to do that work.
    My own building was built in 1960 and I have 5/16 inch thick fir plywood underlayment over a 3/4 inch thick fir 1X6 plank subfloor. That's lasted 50 years so far with no indication that it won't last another 50.
     
    Last edited: Apr 18, 2010
  12. Apr 18, 2010 #12

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    These boards are nailed to sleepers secured to a concrete slab. I'm sure that was the reason for them being underneath the particle board. All I need is something to lay over top of those boards, and it may appear that the wood is cupping from that picture, but after removing the particle board yesterday, the floor seems to be pretty level in my opinion.
     
  13. Apr 18, 2010 #13

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
  14. Apr 18, 2010 #14

    Bud Cline

    Bud Cline

    Bud Cline

    Tile Contractor

    Joined:
    Apr 13, 2006
    Messages:
    284
    Likes Received:
    0
    BALONEY!

    Those boards will move with environmental change of every season. They always have and they always will, that's the nature of the animal. Under carpet its no big deal. Under a hardwood floor, it's no big deal. Under a laminate floor, it can be a big deal.

    If you look closely at the picture you can see the rough edge of the torn particleboard and the crumbled remnants of the fibers piles up.

    Look even closer and you will note that (from left to right) board number 1 is crowned, board number 2 is cupped. Boards 3, 4, and 5 are all crowned.

    It will never stop. Just because they aren't reaching up and slapping you in the face doesn't mean they aren't moving and aren't distorted. It happens everywhere. Millions of homes are built with a similar (diagonal) method and the issues exist in each and every one of those millions of homes.

    Now is the time to correct the problem for good by getting rid of those unstable slabs of firewood and replacing them with suitable structurally sound plywood that will take the moisture that is rising from under those boards and will be even more trapped when laminate goes down. The ability for the moisture to dissipate will be greatly diminished now that the carpet has been removed.:)

    Trust me Kelebay. This is one (more) time you don't know what you are talking about.
     
  15. Apr 19, 2010 #15

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    Mary:

    As for Bud Cline's comments, speak to the Installations Manager at any of the flooring stores in your area. If there are, or ever were problems installing plastic laminate flooring over underlayment over a lumber subfloor, then the Installations Manager would know about it and would advise you accordingly.

    The way I look at it, your 2X4 sleepers under those 1X6 planks are also lumber and will swell and shrink slightly with changes in humidity too. And plastic laminate flooring has seams in it that could easily accomodate the tiny amount of movement of the wood we're talking about. And, on top of all that, wood is a soft material that's easily compressed, and will therefore accomodate a lot of movement on it's own.

    So I simply don't share Bud Cline's views about the need to replace the subfloor. If it were my house, I would replace the particle board underlayment with either a fir plywood underlayment or 6 mm Baltic Birch plywood. But I would keep the 1X6 lumber subfloor unless and until someone who's knowledge I trusted told me otherwise. That's why I say to consult with the Installations Manager on this point.
     
    Last edited: Apr 19, 2010
  16. Apr 19, 2010 #16

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    This is what I know..........I know that it is not recommended by the flooring manufacturer to install laminate flooring over a sleeper constructed subfloor due to not having 18" of ventilation space. However, they will tell you that you can install laminate or hardwood flooring over concrete, so what is the difference, I ask.
     
  17. Apr 19, 2010 #17

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    Bud, I will take another picture of the floor from a different angle for you and post it in my remodel album here at the site; perhaps that will give you a better look.
     
  18. Apr 19, 2010 #18

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

    Emperor Penguin

    Joined:
    Mar 29, 2009
    Messages:
    1,844
    Likes Received:
    2
    Mary:

    Maybe take a picture with something you know is straight laying across the boards to prove they're flat and level.
     
    Last edited: Apr 19, 2010
  19. May 3, 2010 #19

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    OK, we bought some 19/32" plywood to put down over the planks that are on top of sleepers, and I have a question.............the plywood isn't precisely uniform. Where the seams meet, there is some unevenness. How should we address this?
     
  20. May 4, 2010 #20

    scarymary

    scarymary

    scarymary

    Member

    Joined:
    Apr 14, 2010
    Messages:
    21
    Likes Received:
    0
    Here is the dilemma...........if I were going to tear out all those existing planks, then I am left with nothing but sleepers on top of concrete. The room is already framed and had flooring on it previously. Any deviation from what was there previously will create an elevation change, and that is what I'm trying to avoid. I can't make any adjustments to the doorways in the room easily. That is the only reason I am trying to stay within the confines of what was there previously. I have no reason to doubt your experience or knowledge regarding this.
     

Share This Page