Man I'm ripping up a lot of floors these months! I'm dealing with an incredibly uneven subfloor right now. Used to be carpet. Previous owner filled the most egregious valleys with floor leveling compound that's old and turning into dust. So i need to decide the following:
How to fix it? And then what to put down - laminate or vinyl plank?
So I can either hire someone to just put big sheets of plywood down across the entire floor. Generally speaking, if i do this, I won't need to otherwise correct the flooring right?
Or, I could grab my planer, my belt sander, and some levelling compound and do my best to level it out a bit.
In terms for flooring, I'm either doing cheap laminate or cheap ish LVP (it's a rental). The laminate is a bit more forgiving because i have an underlayment but for the vinyl plank if i remember correctly the floor has to be perfectly flat because you don't use an underlayment. The kind i used has sticky edges and you just stuck the edge of one piece to the edge of another.
I loved how easy the LVP was. I didn't need a saw! I'm terrible at a jig saw so even though I've done laminate before it's frustrating and any detailed areas don't look so great.
If i hire someone to put sheets of plywood down, do i still need to use floor leveler? If I use laminate, could I get away with planing down the worst peaks but leaving a bit of unevenness and getting a thick underlayment?
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Super uneven subfloor. What are my options?
Can underlay fix an uneven subfloor?
No — underlay cannot correct bumps or dips. It only provides cushioning and noise reduction. Using thick or multiple layers of underlay will make the problem worse and reduce stability. Levelling compounds, grinding, or plywood are the correct solutions.
What happens if I install flooring over an uneven subfloor?
Installing hard flooring over an uneven subfloor can lead to gaps, creaking noises, and boards shifting or breaking. Over time, this may also void product warranties, as most manufacturers require floors to be installed on a level base.
How flat should my subfloor be before installation?
Most floating floors (laminate, hybrid, engineered) require no more than 2–3mm variation over 2 metres to comply with Australian Standard AS 1884. FloorVenue’s installers always check your subfloor before installation to ensure it meets these requirements.
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Thank you all very much for the advice. I decided to give the planer a go, since worst case scenario, I could rip the subfloor out if I made it worse. It worked REALLY well. I was able to completely get the peak out of the floor, sanded it, and now its level! I think had this been a bigger area, taking it out would have been a better plan, but with there being a lot of gas and electrical I was nervous.
That's OSB flooring. You're not going to be able to plane it down. The planer will, most likely, just pull the chunks out of the board leaving a mess.
As bad as that missing chunk is closest to the camera in the first picture, I'd suggest that you cut out at least some of that board and completely replace it. This will also give you the opportunity to level the new board with the rest of the floor.