# Filling in a large gap in plywood flooring



## Austin1983 (Jul 10, 2011)

I'm working in some territory that I'm unfamiliar with. I own a house built in 1900, and the kitchen floor consists of vinyl tiles on top of fairly new plywood flooring which is sitting on a wooden subloor. The former owner of the house left almost a one inch gap between two plywood sheets. The gap was filled with sheet rock mud which cracked and caused the vinyl tiles to crack. I cleared the mud out of the gap and I was able to see the subfloor. The subfloor had a small crack/gap in the wood which allowed me to place a long screwdriver through it to the underside of the house (only as wide as a screwdriver shaft). I want to use self leveling compound to fill this gap, but I know I'm going to have to seal up the crack/gap in the subfloor prior to using the compound. Should I use silicone caulk to coat the base of the gap to prevent the self leveling compound from running out under the house? Are there any other options that would work better or easier? We aren't looking for perfection, just something to prevent new vinyl tiles from cracking because of gaps. Thank you in advance for any advice.


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## Bud Cline (Mar 12, 2006)

Why Self Leveling Compound? It will break up the same as the other filler did.

It would be better to cut a strip of wood that can be glued and/or nailed in the crack.


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## Austin1983 (Jul 10, 2011)

Bud Cline said:


> Why Self Leveling Compound? It will break up the same as the other filler did.
> 
> It would be better to cut a strip of wood that can be glued and/or nailed in the crack.


Well, I didn't even think of that! What do you recommend for smaller gaps where the width of the gap tapers down? Would a wood filler be okay for those gaps? Also, Should I use a backerboard of some type on top of the plywood to make a cleaner more even surface for the vinyl tiles?


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## Bud Cline (Mar 12, 2006)

> What do you recommend for smaller gaps...


I would suggest you cover the whole project with a 1/4" plywood underlayment and be done with it.


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