Up With the Old!
If the home getting new laminate flooring has carpet on the floors, the carpet must be pulled up and the tack strips along the walls removed. Other preparation is minimal.
It makes sense to hammer down any nails or staples that stick up and to smooth the surface where you pulled up the tack strips. You might also consider laying a 6' straight edge on the floor and see if you have any sags more and 1/8" deep.
The instructions that come with your laminated will suggest filling such depressions with a cement base floor leveler, but that is probably not such a great idea if you have a particle board subfloor. I would see if a belt sander woud let me take enough off the high spots to fix the problem.
You will want to take the time to make sure all the baseboards are removed and that the area under them is smooth and clean. You are going to have to slide your laminate strips into place there and it will be annoying if you wait till then to clean out problems.
This is the kind of water damage commonly found under the carpet. The shower stall is on the other side of the wall and has obviously been leaking. It should be sufficient to bang the staples with a hammer and possibly run a belt sander with a course belt over the high spots....
This particular house had self stick vinyl floor tiles. Some were loose and some were broken. The wood laminate floor could have gone on top of the, but a shingle scraper will take them off without much effort. Removing them would make it easier to spot any other floor issues that might need work.
The floor register you see here shows up in some of the later pictures. It’s a “feature” that you have to work around which will be easier with a good saw. Fortunately the register covers have a half inch lip to cover any measurement mistakes.
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