Installing 12mm laminate over Oriented strand board

[Red]

Hi, I'm trying ton install a floating floor for the first time, its gemwoods brand, the Scottsdale collection merlot.

After removing my carpet I discovered that the subfloor is Oriented strand board ,
https://en.m.wikipedia.org/wiki/Oriented_strand_board

The surface is NOT smooth at all, plus there are big gaps between each board, so Im wondering if its possible to install the floating floor on top?

Thanks in advance for your help and time.

 

[highup]

I have one coming up soon. I know some are much smoother than others. I hope mine is fairly smooth. It will need prep for sure.
The seams will probably need sanding Red. I have a hardwood floor edger-sander and with 16 grit paper, flattening the seam edges can go pretty fast.
The OSB will need some floor patching/leveling compound applied Red. Something like Ardex Feather Finish. Lot's of flooring patch materials available if you can't get that one.
You'll need either a concrete finishing trowel or a drywall spreader and possibly piece of angle aluminum for a screed to apply the leveling compound. Use the angle aluminum for a straightedge to map the floor and find the high and low spots. Sand the high places and fill the low ones. For the overall bumpieness, you might need to screed/float the leveling compound over the entire floor if it's really that bad.

How large of an area are you doing?

 

[Red]

I'm doing 645 sqft, that encompasses 3 bedrooms and 17 stairs, here are some pictures of the subfloor of bedroom #1

Image gallery, osb subfloor

I'd like to believe is even ,but have not used a level to verify, Im holding a piece of chipped wood in my hand in one of the pics, you can also see the gaps there.

I didn't know that I could use leveling compound, I just assumed that the osb will absorb it and swell, thanks for the tip.

Do i need to buy a sander? Or the self leveling compound would be enough?

 

[highup]

Partial repost.

 

[highup]

Hard from the images to say what's best. There's a lot of paint and probably drywall splatter, so it's not just the unevenness of the OSB from what I see........ correct?
It doesn't look horribly bad, just messy....... and messy like that makes it harder to see the problem areas. ....highs and lows or unevenness/flatness.

OSB on stuff like yours is usually installed over engineered joists which are usually pretty flat or even if installed correctly. You need some sort of straightedge in order to locate the highs. lows and especially to check out the floor joists for flatness or consistency.
A good nylon sting pulled tight across the floor would be a decent initial check. Just put some screws or nails in the floor in multiple places along the the floor edges and corners. Make a loop in the string, then loop the string on a nail at floor level, then pull it tight on the other side of the room. Any major problems if there are any, will show up immediately.

Yes, correct about some swelling from the filler/leveler compound. More of a concern would be a few random flakes of the OSB swelling and possibly lifting slightly because of the water in the compound. OSB gets installed and often water gets on it before the roof gets put on, so it's more than just wood chips. There are some pretty strong binders in the OSB so it won't turn into oatmeal if it gets rained on. It's whole lot different than particle board.

Is that a real wood laminate?

 

[highup]

I have a small one of these buffers. Mine is just 13 inches. It was given to me, so I can't complain about the size.
https://www.cityfloorsupply.com/?page=item detail&itemcode=CLBUFFERRS16DC

They turn rather slowly (175 rpm) so they don't make as much dust as you's think. If you could rent one of these for a couple hours, it would evenly knock off the drywall splatter and hit some of the high spots so that you could more easily see what's left to deal with (either more sanding or if you just need leveling or smoothing compounds)

Just be sure to tell the rental place what you plan to use it for.
Just a thought.
You might get by with a scraper or/and a belt sander. I can't tell even tho your images are good. No matter the sander if you need one, use the largest grit paper you can find............ at least 50 grit for a belt sander, and 16, 20 or 36 if you end up finding a floor sander to rent. Larger grit paper cuts better for your needs and makes less dust......... not no dust.

 

[Nick]

I can't open the photos ..
You can get a 6' level at HD for around $40.00 .. If you are going to sand i would get a 3 1/2 open grit .. Will keep it from clogging ..

If you check upload file on right of page . go to your photo , check open .. Post reply .. It will paste the photo in your post ..

 

[highup]

Opened fine using my dialup Nick.
.....try that with Win XP.
It's just paint and drywall splattered OSB Nick. Gaps in the T&G look about 1/8" or so. I don't see any issue with the gaps. Problem from our side of the room is we can't see in 3-D. The paint/drywall splatters make it hard to tell how flat it is.. 12mm is getting really close to 1/2" thick, so that probably helps in some ways.
We have an industrial steel and metal supply place in town. I bought a 3/16" thick 2"x 2" piece of angle aluminum 5 feet long for about $22. It makes a good screed. The 1/8" thick aluminum is a bit flimsy for that. It isn't a level, but it's super straight and flat.

 

[Nick]

Should open on my confuser to Hi..

 

[Red]

Hi guys, thanks a lot for all your feedback, I'll get a cheap sander from HD,
https://www.homedepot.com/p/Ryobi-2-Amp-1-4-Sheet-Sander-S652DGK/205179523


Once I get the surface clean, and sand will post more pictures and go from there.

 

[highup]

Those 1/4 sheet sanders are made more for minor material removal such as the final stages of paint prep. They make fine dust and aren't really for removing chunks.
This would be better especially if they make 50 grit paper for it.
https://www.homedepot.com/p/DEWALT-5-in-Variable-Speed-Disk-Sander-DWE6401DS/203316362
Maybe a local pawn shop has a belt sander or something more heavy duty. I see HD also has tool rentals, so that might be a better option.......... if the tool doesn't seem to work for what you are doing, you are only out a daily or 1/2 daily rental fee.
Tool rental places do rent out those larger flooring sanders and they would make quicker work for the initial sanding of the floor to get it clean.
..........they do however, have a learning curve to learn how to steer them. You have to move slow and with care so you don't put a hole in your wall.

A hand scraper, the pull type paint scraper, would be slow and dust free, but you're gonna want knee pads and plenty of water. Those would clean the floor, but not help in flattening any OSB seam edges or humped up in the chips. You'll need an aggressive sander for that, such as a belt or disk sander.
Once clean, you will be able to lay some sort of straight edge on the floor to check for flatness.

 

[Red]

Understood , I returned the other tool and purchase this instead

https://www.homedepot.com/p/Ryobi-2-6-Amp-5-in-Random-Orbital-Sander-RS290G/205105594

Got 80 paper grit, I'm hesitant about the rental because I only pulled the carpet in one room, the plan is to finish this one before removing the carpet from bedroom #2 and so on.

We still need to live in the other bedrooms while the "construction " is in progress.

 

[Nick]

80 grit is a little fine .. if it is not doing the job drop down to a 40 , or 60 grit ..

 

[Red]

80 grit is a little fine .. if it is not doing the job drop down to a 40 , or 60 grit ..

Will do, thanks

 

[highup]

If you have a shop vac, it will collect more dust than the bag on the sander. You might have to make up a connection tho ......duct tape is your friend.

 

[Red]

Done!, the floor has been sanded with 40 grit paper, I have 3 questions

1. There are places with some paint, the 40 grit would not work there, is that ok?
2. There is one heavy duty nail that pops up about 3 mm from the subfloor, do I need to cut that? (I hit it with a hammer without success)
3. The corners in the room have a small dip 1/4 inch, do I need to do something about that?

Image gallery
https://postimg.cc/gallery/2tgcukhyc/

Could not upload to the forum, images were to big and forum tools did not like that

 

[highup]

The paint isn't an issue unless it also contains chunks of drywall mud that make it bumpy. You want flat, not necessarily pretty.
If you can't drive or pull the nail then definitely cut it off. You can also use a drill if you're careful. Hit the nail with a sharp punch just enough to put a den or dimple in it. Be sure the dimple is in the center of the nail head. Drill first with a 1/16th bit about 1/8" deep, then switch to a drill bit that is about the same diameter as the nail head. The first hole will keep the larger bit centered as you drill. Now just keep drilling until you drill the head off of the nail. add a new nail or screw somewhere close to where this problem nail is located.

You really need a good straight edge of some sort at least 4 feet long to check the floor for flatness. Nick mentioned a 6 foot level. Even a cheap plastic one would be worth having.
Hardware stores also sell angle aluminum in pre-cut sections. A piece 5' long and 1 1/2" by 1 1/2" sides would work. The reason I say this is because you need something flat to lay on the floor to see how flat end even it is. Just using your eyes won't work. Some sort of straight edge is a must have. You said the corners dive off about 1/4 of an inch. How quickly the floor drops off into the corner would determine if it needs filling. It probably does. You won't know where to start filling unless you know where the floor is flat and what point it starts to drop off.
Floor filler might be needed and something like that angle aluminum could work as a tool to screed or float the filler.
There's gotta be a video out there showing the skim coating and floor leveling process.

 

[Nick]

 

[Red]

Thanks for your support, I managed to install the floor on the first bedroom,
https://postimg.cc/gallery/il9976lg/

I'll post more pictures once is cleaned up. My next challenge is going to be the hallway ,this is NOT level at all, there is a slope of about 1/4 inch that runs across all the subfloor in that area.

My guess is that I'll need a T reducer, given that the hallway and the bedrooms floor height is different right?

 

[highup]

How long of a hallway? Does it slope slowly and gently over the length of the hall or a quick 1/4 inch drop?