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Level a plywood subfloor

DaveSNJ's picture

I would like to level a plywood subfloor that is out of level by as much as 1.5" over a 6 ft. span.  I've looked at various approaches and think that the easiest may be to install 2x4 sleepers on top of the existing 3/4" plywood subfloor.  The sleepers would be ripped the 4 inch way and spaced 16" on center.  Then I plan to install 1/2" plywood on top of the sleepers and hardwood on top of the plywood.

Anyone have experience ripping 2x4's along the 4 inch dimension?  What's the easiest way to do that?  Is there a special kind of saw to do this? 

Any comments on this approach? Would you change it in any way? See any potential problems? The total area I have to level is 750-800 sf. Thanks

Make yourself a table saw jig (post #206616, reply #1 of 2)

Make yourself a table saw jig that holds the necessary angle for cutting your sleepers.  Probably you should cut the pieces 3 feet at a time, vs trying to cut the entire 6 feet in one go.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Before I did anything, I'd (post #206616, reply #2 of 2)

Before I did anything, I'd want to know why the floor was out so much in such a short span. No sense building on top of something that has a problem. If you are talking about cutting tapered sleepers to account for the issue, it's seldom that the floor is evenly out of level. I could be different all over and the sleepers, if cut the same, may not solve anything. If tapered 2x4 sleepers would work, there would be no need to cut them the 4" way. Another issue is doors or openings. Increasing the height of the floor will normally effect these areas.

I think I would look into the possibility of removing the existing plywood subfloor instead of building on top of it. Whatever the problem, it might be cured by addressing the framing. If a beam has sagged or lifted, joists were inadequately sized or attached, those problems could be fixed. Sometimes, sistering a new joist along side an existing one can add strength and the sistered joists can be placed level in both directions. This would give you a much better starting point and lessen the height build up.

Beat it to fit / Paint it to match