# 5/8 tongue and groove plywood over old subfloor



## andeeznuts (Feb 21, 2008)

Ok here is the dilly Im going to be doing some tile work in a kitchen and its in a older home. We will be pulling up 7/8 inch thick oak wood flooring and under that is the old 1x6 on a angle....I was thinking of running 5/8 tongue and groove plywood over that to beef up any week spots....Let me know what ya think...thanks


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## kiteman (Apr 18, 2012)

Sounds like a plan! Did the same thing last winter on a farmhouse remodel, except we used 3/4" Advantech. Be sure the old flooring is reeeally well nailed off first and eliminate as many squeaks as you can find before putting down the 5/8". I'd probably recommend screwing it down. Don't forget the glue, including the tongue!


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## Rich D. (Oct 14, 2011)

I dont see any problems with your plan. As long as your original diagonal subfloor is sound and secure. 

Use plenty of glue and screws keeps the squeeks down. You really want to make the 2 into 1...


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## mrcharles (Sep 27, 2011)

Are you going to use backer board or a mud base?


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## andeeznuts (Feb 21, 2008)

ditra


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## Morning Wood (Jan 12, 2008)

I think 5/8 or 3/4 is a good idea like everyone has recommended. Lots of glue and definitely screw it down. I'd screw or nail the old boards too. I would also check the floor joists and make sure they are adequate size. If they need to be beefed up, u might want to take up the boards too.


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## moorewarner (May 29, 2009)

Aye to all of the above, screw rather than nail (and definitely old boards to joists), and second Morning's reminder on span/deflection check.

Can anybody vouch for this calc's results (which I have used in the past)?

http://www.johnbridge.com/vbulletin/deflecto.pl


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## Rio (Oct 13, 2009)

Glue, screw and tattoo but for the screwing part we've used Halsteel coated screw nails and when they go down they don't come back up; you'll destroy the ply before pulling up the screw nails


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## Spike7 (May 18, 2012)

*sspike7*

don`t forget a moisture barrier . tar-paper should most likely be put down before you plywood . at least thats the way we do it in south florida( big humidity issues here)


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