Underlayment gap filling question

Discussion in 'Vinyl Flooring Q&A' started by chuck, Aug 29, 2017.

  1. chuck

    chuck New Member

    I am trying to install fiberglass backed vinyl on top of a birth plywood underlayment.
    I left a 0.08 inch (one nickel thick) gap between the plywood panels to allow expansion. But somebody suggests me to fill the gap using Henry 345 floor patch. Do I really need to do that?
  2. kwfloors

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

    Yes. You need to patch it with a cement based patch. Thing is, if anything is a line or bump or speck on that floor it will show through the vinyl when its done. I use a Clarke edger and sand those joints just a bit before I patch them. It flushs or dishes the seams a little to make the patch bite good. After I patched and its dry, I take a hand sander, not electric, and sand the joints smooth. Sometime latex milk over the patch so its sealed up and doesn't dry up the adhesive I'm doing. I also patch every staple or nail in the floor sometimes too.
    • Agree Agree x 1
  3. chuck

    chuck New Member

    Great, thanks.

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