Plywood over old glue?

Discussion in 'Floor Preparation' started by Homerepairted, Dec 30, 2017.

  1. Homerepairted

    Homerepairted Handyman

    I am new to the forum. I do general handyman and home repair work. I have a customer that has a restaurant that had some flooding in the restroom and a utility area. Servepro came in and took care of the flooding damage and I am going to be putting it all back together. The old sub floor still has some sort of notched glue from some form of tile (I don't think it is morter) and I was curious if I can put resin paper down and a new 1/4" plywood layer down screwed every 4-6 inches in the field and every 2-3 on the edges and put the new VCT tile down on the new plywood. Thank you in advance.
  2. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    The only concerns I'd have with your plan is that as much of the existing adhesive notch were scraped down smooth so as to ensure the new ply lays flat, fastens securely and doesn't make any sounds from movement caused by laying over a tacky, irregular, old glue. If it's at all tacky be sure to "dust" over it before the paper and ply.

    Otherwise your strategy is standard operating procedure for laying new resilient flooring over old flooring or adhesive when removing the contaminated, exising floor or ply is prohibitive due to factors like asbestos or wall/counters and such built on top.

    By all means if the existing ply/substrate would be easy to remove Rule #1 would dictate you demo down to a fresh start to avoid building castles made of sand.
  3. Homerepairted

    Homerepairted Handyman

    Thank you. Removing old sub floor is not really an option but sanding down high spots of existing glue, and then using resin paper and 1/4" is going to be the way to go.
  4. Mark Brown

    Mark Brown On The Surface Flooring I Support TFP

    Skip the resin paper and get to work mate :)

    If their are lumps and bumps of glue then one might be advised to scrape it off. If it is just small amounts of old adhesive... well half the time that IS why I put new plywood down.
    • Like Like x 1
  5. Homerepairted

    Homerepairted Handyman

    Thank you Mark!
  6. Mark Brown

    Mark Brown On The Surface Flooring I Support TFP

    why would you contemplate rosin paper??
  7. Homerepairted

    Homerepairted Handyman

    to cut down on any potential squeaking from the 2 layers of wood rubbing together. Insurance let's say
  8. Jim McClain

    Jim McClain Owner/Founder Administrator

    Insurance against improper installation of plywood underlayment? The best insurance is using sound practices and quality materials. Rosin paper isn't in that recipe.
  9. Homerepairted

    Homerepairted Handyman

    Not my improperly installing (and not what I said). Insurance against any squeaking from two layers of plywood together. Although I will be screwing every 2 inches on the sides and every 4 inches in the field, I believe in an ounce of extra prevention.
  10. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Noise is created when the plywood moves vertically against the side of the fasteners.
  11. Homerepairted

    Homerepairted Handyman

    I have had to fix squeaky floor boards before and those are horizontal movements. I have been taught that in other situations to place Rosin paper or felt in these situations. It may be overkill but it certainly will not cause any harm and certainly "could" help. With that said, I appreciate the feedback. But the original question still exists. Am I OK with my plan with or without sanding down any and all raised areas from old glue.
  12. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    You don’t know me and my equipment!

    I use to always grind plywood, OSB, whatever to get the next layer to bond as tightly as possible.

    I’d really like to see a close up. Tile is a shape to me, you mean ceramic or vct, I assume it was a mosaic. A mastic was used? We run into that occasionally, maybe 5% if not less due to cost ratio of mortar.

    I think if Adhesive is squishy it will give under weight.
  13. Jim McClain

    Jim McClain Owner/Founder Administrator

    Taught by who, flooring professionals? You are adding a flexible membrane between 2 layers of plywood. That could cause adjoining sheets of plywood to rub against each other, creating a squeek. It's a gamble you don't have to live with, but the customer will. And the failure may not happen for some time. It may never happen, but it's still a gamble. No felt is necessary between the underlayment and the subfloor.

    You can choose what to learn here, but not what knowledge our pros share. This is a public forum and this discussion will be here for many years and viewed by hundreds or thousands of other DIYers, handymen and pros long after you have forgotten this project. It's not just you that may or may not be helped by this.

    Remove the adhesive ridges as best you can. Sweep a fine powder, like dry floor patch mix (not flour - don't feed the bugs and microorganisms) over any still sticky adhesive residue. Then install an underlayment quality plywood.

    This is not a home repair, Ted, it's a commercial establishment. The owners should have contracted with a professional. We all hope you are up to the task.
  14. Homerepairted

    Homerepairted Handyman

    I am completely up to the task (and a professional). I am doing a complete restore of a space that had been flooded.

    I am pretty unimpressed with this forum and the people in it. Attitude is pervasive and not very welcoming so I will now remove myself from this board and find people that have a sense of decency to discuss projects. You all have ZERO idea what I do, who I am, or what I know. I thought this was a place to share thoughts and ideas and gather knowledge. There is always more than one way to skin a cat but it is nice to know how others do it.
    • Funny Funny x 1
  15. Floored by Newman

    Floored by Newman Floored by Newman

    Eliminate high spots. No paper needed as it achieves nothing. Staple please do not screw...
    • Agree Agree x 1
  16. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I use to screw down 1/4”. It got very time consuming, then needing patch. We ended up using 1” cleats that didn’t damage the surface so only the joints needed feathering.

    I can see the attitude, maybe Jim needs a snack/nap.
    • Like Like x 1
  17. Jim McClain

    Jim McClain Owner/Founder Administrator

    Hmmm, possibly. :hu:
  18. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Naps are good, not always optional, caffeine sometimes helps when I’m off it’s @ 2:30 pm.

    I don’t think I’d put vct in a bathroom, probably LVT so it won’t show cracks
    • Like Like x 2
  19. Chris 45

    Chris 45 Director of P.R. on some deserted island. I Support TFP

    Unless you wax and maintain the VCT, moisture would just make its way through to the underlayment. I’d say sheet goods would be more appropriate for a bathroom.
    • Like Like x 1
  20. kwfloors

    kwfloors Fuzz on the brain Charter Member I Support TFP Senior Member

    I do use some kind of paper under the ulay, not resin paper. I use non coated paper, newspaper works too.

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