# How to even out a patched-in plywood floor



## m2244 (Jan 28, 2013)

Hello,

I am helping a friend with his bathroom floor. They had a leak, he cut out a 2-foot square section of the plywood, we patched it back in but the old and new plywood does not match up perfectly. In some spots the new plywood is too low. The flooring they are going to install is this thin linoleum stuff so we need to even the subfloor out fairly well.

What should we use? Is there something similar to sheetrock mud? I have seen stuff that you poor on but this is around a toilet so there are holes, I don't think that this liquid stuff would work. Is there soemthing you can put on with a trowel?


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## nealtw (Jan 28, 2013)

http://www.dap.com/product_details.aspx?product_id=341


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## jmc0319 (Jan 28, 2013)

nealtw said:
			
		

> http://www.dap.com/product_details.aspx?product_id=341



I used this product for the same purpose and it worked really well.


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## m2244 (Jan 28, 2013)

Great. Thanks guys.


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## Rusty (Jan 29, 2013)

Well I would use a cemetious based floor patch and then 1/4" underlayment grade plywood. Oh, I am an Armstrong certified vinyl installer. Been doing it for 40 years.


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## Jaz (Jan 30, 2013)

Absolutely you need a cementitious patch and then an approved underlayment.  Resilient flooring does not get installed over the subfloor.

Jaz


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## Wuzzat? (Jan 30, 2013)

The cementitious stuff being brittle will fragment when flexed by the weight of people.  Is this OK?

Since Linoleum is not brittle or inflexible, I'd put shims underneath the plywood if that area is accessible.  
Glueing shoebox cardboard on top of the plywood and sanding flat and level may also work but you should topcoat the cardboard with some waterproofing, like polyurethane/varnish/old paint, then whatever Linoleum needs to have, to bond to.

Leveling within 1/16" is close enough, right?


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## Rusty (Jan 30, 2013)

Wuzzat? said:


> The cementitious stuff being brittle will fragment when flexed by the weight of people.



Where would you get that idea? That's why you don't used gypsum based, it is brittle. Cementious based is not. I have been installing resilient flooring since 1973. Believe me, I have installed stuff that cost $50-$80 a sq yd, using cementious based with 1/4" underlayment grade plywood with no failure.


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## Wuzzat? (Jan 31, 2013)

samfloor said:


> Where would you get that idea?


From here

ce·men·ti·tious  
/&#716;s&#275;men&#712;tiSH&#601;s/
Adjective
Of the nature of cement: "a high-strength cementitious mortar that set within 1.5 hours".

I stand corrected.


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## Fredartic (Apr 16, 2013)

nealtw said:


> http://www.dap.com/product_details.aspx?product_id=341



Could it be used in mobile home that is not on a slab, but has been leveled last year? Is there a chance to crack in that condition?

Thanks


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## nealtw (Apr 17, 2013)

If there is a chance of the floor moving, it wouldn't be my first choice, have a look at posting above by Samfloor and Jaz


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## Jungle (Jun 13, 2013)

I would use this self leveller, the magic of gravity will do a much better job than the human eye.





There is a acrylic primer to use before hand.

After that you can put your flooring right over it, so it says on the package. It is cement and some polymers.

Floors are deceptively difficult to level, shimming it would be difficult not to mention creaky. Cardboard will depress/degrade and therefore useless, if you want to do that you can use roofing felt.


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## bud16415 (Jun 13, 2013)

I just pulled up the linoleum in our new old house in the second floor bath the other night. It was laid over tongue n groove flooring and some sort of tar paper first then layers of newspaper for padding I guess, that kind of dated the flooring job. 

I spent way too much of the rest of the night reading the 1936 newspapers. They were amazingly preserved in the floor. Not too many electronics ads back then but bikes were pretty inexpensive.


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## Jaz (Jun 13, 2013)

People used whatever was handy to help hide the gaps in the plank subfloor.  It was common to use tarpaper as the underlayment under vinyl/rubber tiles and sheet vinyl or linoleum up to the '60's.  Plywood was not used much in the subfloor system and 1/4" underlayment didn't become popular until the '60's.  

Jaz


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## digitalbum (Jun 24, 2013)

Ok guys I think I got it.  Thanks for the advice.


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