Use a large hand plane like this:

I installed vinyl plank throughout my first floor; 1200 square feet. The rooms I did before thinking about this show every little bump or seam. Most people don't see the defects, but I sure do. They drive me nuts. I wish I thought of this sooner.

Make sure the blade is set to take tiny ribbons of wood and is real sharp. It will go through the wood like butter. Makes quick work and you can get that area completely smooth.

Answer from Evil Elf on Stack Exchange
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DIY Home Improvement
diychatroom.com › home › forums › home improvement › flooring
Subfloor uneven along one seam line | DIY Home Improvement Forum
Lastly, hit the seams with self leveling floor compound and then install the flooring of your choice. ... If you find no other obvious cause, it's pretty common in this area for the subfloor to get wet during construction before the house gets "dried in" with roof and windows.
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City Floor Supply Blog
blog.cityfloorsupply.com › home › how to fix an uneven subfloor
How to Fix an Uneven Subfloor | City Floor Supply
May 25, 2023 - This usually means that either the floor itself or the subfloor underneath is experiencing problems. To rule out the floor covering, test it with an appropriate moisture meter to determine if it’s the source of the problem.
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Houzz
houzz.com › discussions › 349617 › subfloor-uneven-how-to-level
Subfloor uneven, how to level?
I ripped up the old hardwood in the kitchen. The plywood subfloor is uneven. Now I want to lay a quality laminate flooring with underlayment. The room is a kitchen and a dining area measuring 25' x 15'. The uneven part of the plywood subfloor runs width of the center of the entire room. The plyw...
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Reddit
reddit.com › r/homeimprovement › super uneven subfloor. what are my options?
r/HomeImprovement on Reddit: Super uneven subfloor. What are my options?
January 11, 2019 -

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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Reddit
reddit.com › r/homebuilding › dealing with uneven osb subfloor seams
r/Homebuilding on Reddit: Dealing with uneven OSB subfloor seams
June 22, 2024 -

How do you handle bad joints like this in T&G OSB (LP)? I was walking a new build (not mine) and caught this.

I know that you can plane swelled seams, but that seems less possible here, plus you'll be grabbing nails. These are glued and nailed. Should these be yanked and done over? Overall, the subfloors looked good, and all long seams were clean.

Added a second example that was smaller. It's easier to see, possibly fixed with a different solution.

I should have cleaned this larger one up for a proper picture.

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A Crafted Passion
acraftedpassion.com › home › renovating? learn how to fix an uneven subfloor
How to Fix an Uneven Subfloor | DIY Home Improvement
See how to fix an uneven subfloor before installing laminate flooring if things aren't even. Follow these steps before putting down flooring.
Published   December 4, 2024
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Marshalltown
marshalltown.com › home › workshop › flooring & tiling › fix uneven floors in six steps
Fix Uneven Floors in Six Steps - MARSHALLTOWN®
Before you put down your new floors, underlayment is a great way to ensure your subfloor will be level.
Find elsewhere
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Quora
quora.com › How-do-you-fix-an-uneven-plywood-subfloor
How to fix an uneven plywood subfloor - Quora
Answer (1 of 4): Depends on how uneven it is and it’s cause. Let’s start with the simple fix. if the unevenness is minor, 1/2” or so deviations or less, and is not related to a defect in structure but rather is simply from slightly sagging floor joists or even cupping floor joists over ...
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Canadian Woodworking
forum.canadianwoodworking.com › home › home improvements › home improvements
Fixing uneven subfloor - Canadian Woodworking and Home Improvement Forum
Re: Fixing uneven subfloor If you have aces to the joists below you could try to drive shims between the joists and sub floor( but not if you have tiles on or close by the area. Ive done this a number of times an found that glue will act as a lubricant and then hold the shim in place.
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Reddit
reddit.com › r/carpentry › any flooring folks who can answer a subfloor question - staggering seams on short or long side?
r/Carpentry on Reddit: Any flooring folks who can answer a subfloor question - staggering seams on short or long side?
September 20, 2021 -

Currently installing 3/4” t+g plywood subfloor throughout our entire main floor (about 500 sqft open concept). Joists are 18” OC (old house), gluing and screwing sheets perpendicular to joists, plan to put underlayment and 3/4” hardwood on top once this is done.

Everything I’ve read says to stagger the seams and avoid four corners meeting. Makes sense. But they never specify whether the stagger needs to be on the short or the long side. They always show it on the long side. However, due to our houses layout, the joist leveling work involved, and the fact that we’re living through the renovation, it’s much more feasible for us to stagger on the short side and work in 8 foot sections.

Anyone know if this is a bad idea - and if so, why? Either way, we will avoid having four corners meet, but beyond that, my amateur brain cannot figure out whether it’s better to stagger on the long side or short side - and if long side is better, why, and how big a deal is this?

Thanks!!!

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Home Improvement Forum
house-improvements.com › home improvement forum › forums › interior
Filling seams in subfloor???? - Home Improvement Forum
I'm confused. Before I laid down some subfloor, everything I read/watched said to leave a 1/8" expansion seam around plywood panels. Okay, no biggie. Seams dutifully left. But, I just happened to come across some videos and pages that show us how to fill those seams for painting plywood flooring ...
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Hardwood Floors Magazine
hardwoodfloorsmag.com › 2023 › 03 › 01 › inspectors-report-uneven-subfloor-not-an-easy-fix
Inspector’s Report: Uneven Subfloor: Not an Easy Fix
February 28, 2023 - Consequently, the flooring needs to be replaced, and the subfloor repaired in that area. The installer should have checked the flatness of the area where the wood flooring was to be installed, and prepared the subfloor as necessary. There is no easy fix for an uneven subfloor under a floating floor application.
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The Spruce
thespruce.com › fixing-wavy-wood-subfloor-1821092
How to Flatten an Uneven Subfloor
April 4, 2023 - However, if the subflooring material was substandard—built with non-regulation thin sheets of plywood or another material—it's possible your subfloor will be uneven and need alterations, such as leveling the floor with new plywood, before ...
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Rejuvenationfd
rejuvenationfd.com › blog › how-to-fix-uneven-floors
How to Fix Uneven Floors: Causes, Techniques & Cost
October 9, 2024 - This technique is commonly used when a hardwood floor has mild unevenness but doesn’t require a full refinishing. Shimming: If the subfloor is uneven, shimming can be used to fill in gaps between the floorboards and subfloor.
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AnandTech
forums.anandtech.com › home › social › home and garden
How to level an uneven OSB subfloor before laminate? | AnandTech Forums: Technology, Hardware, Software, and Deals
April 27, 2015 - Obviously, most such unevenness is at a joist, so you'll need to remove the nails first. You could alternatively raise a lowered joist if it's accessible from below and not glued in by shimming it, or remove the piece of subfloor and grind just the joist itself down (way quicker than griding down a larger piece of OSB where it crowns the joist).
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DIY Home Improvement
diychatroom.com › home › forums › home improvement › building & construction
Floor bows at subfloor seams. | DIY Home Improvement Forum
How do you have any way of knowing that based on the info in the OP's post? The thickness of your subfloor is irrelevant here. The only seams in your subfloor should be directly on top of a joist - NOT between joists. I think you have the right idea by bracing it from below.
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Hardwood Flooring and Stairs
hardwoodflooringtalk.com › forum › uneven-subfloor-t5872.html
Uneven subfloor. : Hardwood Flooring For Contractors and Installers
I'm not floor guy though did work for one right out of HS for several years. I'm installing cabinets in a semi-custom home, and the ...