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Will 1/4" plywood overlay add any real stability to subfloor?

Will 1/4" plywood overlay add any real stability to subfloor?

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  #1  
Old 02-21-16, 08:37 AM
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Will 1/4" plywood overlay add any real stability to subfloor?

My house was built in 1985 and they used 5/8" "waferboard" as the subfloor. My understanding is that waferboard was the forerunner to OSB. Many wood floor manufacturers don't mention waferboard in their installation requirements and cite 3/4" OSB or plywood minimums.

If I add a 1/4" plywood, glued and screwed to the top of 5/8" "waferboard" will that add to the strength of the waferboard?

Thanks
 
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Old 02-21-16, 08:43 AM
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I'm no expert in this type of thing. But I want to know the correct answer to this also. However, in my opinion I don't think 1/4 plywood is going to give you much strength or support. I suspect the experts here will tell you either remove existing floor and use 3/4 ply or add 1/2 to 3/4 to existing floor. Lets see what they say.
 
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Old 02-21-16, 08:44 AM
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What's the problem you're trying to remedy?
 
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Old 02-21-16, 08:45 AM
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It's not going to add any strength.
And screws and glue should not be used when installing under layment!
 
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Old 02-21-16, 09:16 AM
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I second joe's opinion.

and need more words.
 
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Old 02-21-16, 11:29 AM
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"waferboard" is a viable predecessor to OSB. Particle board is a failure for which the inventor should have been sent off to a remote island. Do you have any pictures of the subfloor so we can see which one you have? Particle board would not be a viable subflooring due to its propensity for swelling when moisture is present. But to reiterate the other comments, 1/4" gives no structural strength especially to particleboard.
 
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Old 02-21-16, 12:20 PM
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Minimum 3/4" OSB or 5/8" plywood for nail down applications. It is for holding power of the stapes or cleats. Particleboard is not stable enough as it will not have the holding power needed and any water event and it swells and turns to dust. Here are the National Wood Flooring Association guidelines.

http://tinytimbers.com/pdf/nwfa-install-guidelines.pdf
 
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Old 02-21-16, 04:40 PM
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Thanks

Thanks for all the input guys. Let me answer the questions that came up:

First, it is waferboard not particleboard. See pic Name:  subfloor pic (2).jpg
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Second, I noted that many hardwood manufacturers require 3/4" subfloor. My subfloor is 5/8" so I want to add the 1/4" to bring it up to 3/4".

Third, it's not a true underlayment as used in vinyl installations. I will be installing hardwood.

Hope I answered your questions and I am looking forward to some more of your ideas.
 
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Old 02-21-16, 06:40 PM
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Have you measured this OSB? If you have a floor register remove it and see if you can measure it there. I believe you have 1/2", but stand corrected if not. I would install an additional 1/2" on top of what you have and not screw it to the joists, nor glue it down. Miss the joists.
 
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Old 02-21-16, 06:54 PM
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Hi Chandler
I did measure it and it is 5/8". Why would you think it is 1/2"? You have piqued my interest! I am also interested in knowing why you wouldn't screw the new 1/2" to the joists or glue it down.
 
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Old 02-21-16, 07:32 PM
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I have not seen a lot of 5/8" OSB or waferboard, and question why it was used rather than 3/4". If it is 5/8", so be it. I would still add 1/2" to it. Your subflooring is firmly screwed/nailed to the joists at present. The second layer will need to be independent from the bottom layer. I know it doesn't make sense, but they will move, ever so slightly and having them both fastened to the joists will keep that movement from happening.
 
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Old 02-21-16, 07:56 PM
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1/2" would probably have swollen up to be 5/8" thick by now. If you have any access to the floor below, look for the APA stamp and tell us everything it says. IMO it's more likely to be 5/8 than 1/2. You would have to be a real idiot to put 1/2" on a floor. edee_em, could you tell us your joist spacing? Is it 16" on center, 19.2 or 24"?

I don't know about it being "firmly screwed", Larry. Those look like drywall screws. They are notorious for the heads popping off when used as a deck screw.
 
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Old 02-22-16, 04:08 AM
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I really meant that as a question, but it didn't turn out that way. I wanted to know IF it was firmly screwed/nailed throughout. Where's Joel when you need him?? Yeah, seeing those screws look like a patch job to stop a squeak, hopefully and the rest of the floor is not that way. Thanks for the catch, Brant.
 
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Old 02-22-16, 05:46 AM
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XSleeper, the joists are 16" oc. The drywall screws is what we were told to do back in the early 1980's. We listened to the "experts" of the day, perhaps the wrong experts but we did listen!! I am trying to find a stamp I can read. Will get that as soon as I can.
 
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Old 02-22-16, 06:36 AM
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It's very common to see 1/2 sub flooring in older homes, makes no since to do it that way, but it is what it is.
Many times I've seen where they went over the 1/2 with 5/8 of 3/4" while it was being built, to me that's like building the floor upside down.
Those screws are a huge no no.
There to brittle and corrode.
 
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Old 02-22-16, 12:54 PM
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XSleeper's request

XSleeper

Here is the information I was able to see on the stamp:

First Line: TECO TEST (Equivalent to APA???)
Second line: Waferboard
Third line: can't read
Fourth line: 2-M W
Fifth line: 5/8" - 40
Sixth line: PANOFOR
Seventh line: Panofor Inc.
 
  #17  
Old 02-22-16, 05:10 PM
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Difference between oriented strand board and water board in a nut shell. Wafer board is randomly aligned wood flakes - Oriented Strand Board are the same flakes "Oriented" for stregth or specifically aligned so as to make a stronger product. http://osbguide.tecotested.com/pdfs/en/tb103.pdf So, waferboard is an inferior product to OSB which states the industry standards are minimum 3/4" (see previous nwfa document chapter 4). 1/4" plywood does not add structural integrity to a floor application and does not have the nail holding capacity. Resultant finished height (5/8" + 1/4") does not equate the same strength as a solid piece of material at the stated thickness.

Additionally as mentioned, drywall screws are not rated for flooring application. If you would like to see why, take a drill and start backing out the screws. You will find a lot of them simply break off when you try to back them out.

If height is an issue, replace the 5/8" waferboard with 5/8" Plywood. Otherwise, you can add 5/8" ply on top and then look at a thinner flooring product such as a 3/8" engineered. Hopefully, you don't shoot the messenger. We have provided some documentation and the recommended best practices. Please use that in your analysis as I'm sure if you ask enough people, eventually someone will give you a green light answer to your question. Doesn't mean it is correct, but it will validate your request.
 
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Old 02-22-16, 07:53 PM
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I believe everything everyone has said czizzi and we don't shoot messengers or most people, for that matter, up here . I got my answer about the 1/4" not adding anything to the floor and will plan accordingly. My additional posts were to answer questions people asked me. I'm not looking for someone to say it's okay when it's not.
 
 

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