# Stay with 5/8� subflooring or upgrade to 3/4"?



## Rover4 (Aug 2, 2011)

*Stay with 5/8” subflooring or upgrade to 3/4"?*

My wife and I just bought our first home (built in 1977). Previous owner had indoor dogs. We tore up the carpet and padding in the living room (12’x19’) and found a half dozen spots where the subfloor (5/8” tongue & groove plywood twisted nailed 16” O.C.) is saturated in dog urine. I’ve already cut out a 10’x4’ section of the subfloor and still have another 4’x4’ section to go. I’m thinking I’ll go get a few sheets of 19/32” plywood and glue it and screw it using 2” deck screws to replace what I cut out. I found 6 to 8 squeaky spots too so I’ll add some 2” deck screws to the exiting subfloor in these squeaky sections as needed. Then I’ll call a guy in to lay new carpet. 

Some say 5/8” is the bare minimum for a subfloor. I’m half tempted to pull up ALL the existing 5/8” and lay new 3/4" tongue & groove plywood with glue and screws. But, is this upgrade worth my time and money? Who thinks this would be overkill? Who thinks this upgrade would be a good idea?

I’ve got the same 5/8” subfloor on the steps leading upstairs and in the upstairs bedroom. The master bedroom (11’x13’) has what looks to be a bowed floor joist in the center of the room, which raises the floor about a 1/2". If the common response is to go for the 3/4”, I may decide to do that throughout the second floor too. 

Thanks for your feedback.


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## oh'mike (Sep 18, 2009)

That's a lot of work for little gain.

A better solution if you find the 5/8" has more flex than you like ,would be to add another layer of 1/2" over the top of the existing.


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## Bud Cline (Mar 12, 2006)

True 5/8" is the building code minimum in a lot of places. True that more is better.

Your problem is going to be that your walls are built on top of what is there now. To remove it would be a major task and of course you would have to cut it flush along all of the walls. This is also going to require the removal and resizing of all the door jambs and casings including the exterior doors.

Iffin' it was me. I would use a pet urine enzyne eradicator to get rid of the odor and then add another layer of plywood to what is there now. That would be a little easier to accomplish.

There is a high likelyhood that the existing 5/8 is also glued to the floor joists. Total removal could turn into a nightmare.

I see oh'mike types faster than I do.


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## JazMan (Feb 17, 2007)

Absolutely what Mike & Bud said.:thumbsup:

Paint the old floor with this; 

http://www.rustoleum.com/CBGProduct.asp?pid=406

Jaz


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## Rover4 (Aug 2, 2011)

Thanks! You guys are great! I went back to the house and yep, it does feel like the 5/8" has a slight flex to it. Looks like laying down 1/2" plywood on top of the 5/8" should be pretty straight foward. I *might* end up with a slightly higher transition walking into the two bathrooms and kitchen, but that's easily fixed when I get around to redoing those floors. 

And thanks Jaz for the tip about "Clear Bin Sealer". 

Looks like I've got my weekend planned out. Thanks again guys!


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## tonydi (Jul 29, 2018)

I have a similar situation, where i have a 5/8" t&g subfloor that has a dip. Can i use shingles to level and add 1/2" ply over top for a flat level surface? I have seen a post that it was done w/ 3/8" ply, but feel it won't have the necessary strength. Please advise. btw. I will be nailing 3/8 engineered bamboo as my flooring.


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