Excorcism of a Subfloor

Todays story is about an idiot. A royal idiot. One that would be proclaimed king of his idiot empire. Maybe there’s more than one of them… it could be a whole dynasty of idiots!

Many of you know how I feel about underlayment. It’s great until you have to tear it out. It then becomes the personification of anger, hate and people who talk in the theater. Yesterday we met the worst underlayment I have ever heard of, fact or fiction.

It all started with tile. Ceramic tile (have you ever had a ceramic sliver?). Underneath the tile was vinyl tile (rubbery squares with sticky bottoms and decorative tops), which was on top of what may have been the original linoleum. The linoleum was glued to this underlayment.

Most people (the sane ones) use plywood as underlayment. The cheap ones use OSB (which is far inferior and much more annoying to deal with). Whoever did this floor used particle board. In case you don’t know what that is, let me explain it to you. Take sawdust… nice fine sawdust. Add wood glue and stir. Now compress it as it dries. Voila! You’ve got particle board.

Particle board in itself, isn’t a problem. Sure it’s kinda heavy and a bit crumbly, but it’s alright when it’s alone. As you’ve guessed, this particle board was not alone.

First of all, they nailed it down. Not with finishing nails, but large flat-headed nails. Those held pretty well, and caused a lot of crumbling. But that wasn’t the worst. What I’m about to tell you may frighten you, and cause you to wonder how someone could be so… well… they were either brainless or very very mean and angry. Ready?

They glued it down! Glue! Were you paying attention when I told you how particle board was made? Gluing little crumbs of wood together! That means that the underlayment was now effectively the same peice of wood as the subfloor! And we had to remove the underlayment, leaving the subfloor in good condition.

As you can imagine, we tried several methods (scrapers, pry bars, chisels, claw hammers), and nothing seemed to work. We finally found a method that worked pretty well. We cut the whole floor into 3-4 inch squares with a skill saw. Sounds more than a little bit excessive, no? Then we were able to use a tapping block and a sledge hammer to hit the squares from their sides and knock them loose. Not all of them came out clean, but most did. The remainder was still hell to get out. So we brought back the fish. It worked pretty well, but it still wasn’t perfect. All in all it took us 35 man hours to remove some underlayment. Dumb.

That’s it for now… I need to go to bed.

19 Responses to “Excorcism of a Subfloor”

  1. John Ambrose (jma89) Says:

    The Fish… Nice. Now, did you use the sanding, grinding, or saw attachment? 😎

  2. Stevish Says:

    Interestingly we used all three. throwing a 7 inch saw blade on there was tons of fun 😀

  3. A True Worshiper Says:

    Reminds me of some of the horror stories Ian tells me about his job. Some people can be real idiots! Our house in Michigan didn’t have hardly any studs and some walls didn’t have any. Why do people believe they can do it themselves??? Leave it to the professionals, folks. Ha ha I got a compliment in there for ya. 😉

  4. M. Zepeda Says:

    So, was the particle board removal a success? I am faced with the same dilema. But I am the one who is responsible for gluing down the underlayment. Back 26 years ago as an amateur not knowing any better, I followed the instructions of the people that sold us the house package, and glued down the particle board. I now have to remove it and replace it with plywood so we can install a hardwood floor.

    I quess I will suffer the consequences of FOLLOWING the instructions of seemingly knowlegeable people. (Capp Homes)

  5. Stevish Says:

    Heh… That’s unfortunate.

    Yes we were able to remove the particle board. It’s basically a matter of cutting it into a grid of 4 inch squares (with a circular saw). Then find a starting place of maybe 3X2 squares that you’re able to remove. Once you have that, you can get a “tapping block” that’s about an inch thick, 3 inches wide and about 12 to 18 inches long. From there, what we did was put the tapping block in place next to three squares of particle board, stood on the corners with a sledge hammer held out in front of us. Then we’d swing down between our legs, hitting the tapping block hard about 3 or 4 times. That process usually loosened about 12 of the squares, which we proceeded to simply pick up off the floor.

    It’s hardly 100% though. You gotta hit the particle board where it has a good, intact, square side. Sometimes you’ll hit it from the sides and they’ll just crumble. That’s when you have to get creative… We ended up using an orbital sander like the one in the picture at http://www.toolweb.com/pics/MLW5540.jpg, only with a sanding disc insteat of a polisher. We just sanded down the parts we couldn’t get up. Ours was a very aggressive sander (same kind as in the picture) and had a 9 inch sanding disc, and we probably used 50 or 36 grit sandpaper. You just have to be careful not to sand divots into the subfloor… although if you’re putting down a plywood underlayment, you probably won’t have to worry about a few dents here and there. You also have to be careful of nails that will tear up a sanding disc in no time flat. I would get at least three discs.

    That’s about all the advice I have on that one. Let me know if you have any other questions…

  6. Stevish Says:

    Also, as a disclaimer, gluing down particle board is an easy, and cost-effective way of installing an underlayment… it just makes for a lot of work if and when you have to rip it up.

  7. Zip48 Says:


    An update on my experience with the glued down particle board underlayment.

    It wasn’t nearly as bad as you had described. This was probably due to the fact that the glue some 26 years ago was inferior to todays glue.

    I found that the best tool for removing the particle board was a good old roofers shovel. You know, the ones they use to take up old shingles on a roof. It worked extremely well.

    The problem I had was removing slate from an entry way. It was laid on plywood. What a nightmare!! I ended up ruining the subfloor under the plywood underlayment and had to replace a small portion of the subfloor.

    I replaced all of the particle board with plywood. I am now ready to start the flooring.

    Do you have any tips for installing 3/4 inch Brazillian Cherry flooring? I have laid both Bamboo and oak without issues but this cherry is really hard. Any advice would be most appreciated.

  8. Stevish Says:

    Yeah, that Brazillian Cherry is really a lot harder than oak. We have installed it before, but it was prefinished. If yours is not prefinished, then I do not envy the time you will have to spend sanding it.

    We really didn’t have to do much different to install it. We use a Bostitch Stapler, and didn’t really have any problems as long as we didn’t staple within about 4 inches of the edge of a board. Stapling close to the edge is a sure way to split the tongue and make that part of the floor just a little weaker. The times we did have problems were when we had to top-nail something. We were using 16 gauge finish nails in a Porter Cable power nailer. Several of our nails simply crumpled into the surface of the wood without really penetrating. The only real way to avoid this is to pre-drill smaller pilot holes. But with a power nailer, it’s pretty tough to hit an existing hole, as I’m sure you know. Your other option is to top nail with a good ol’ hammer and nail set.

    Anyways, I hope that helps. If you have any other questions, feel free to ask.


  9. Stevish Says:

    You also may want to check with my boss over at HardwoodCafe.com. He’s the one who taught me everything I know about the subject, and may have some more advice.

  10. M Zepeda Says:


    Fortunately the Brazillian cherry is finished. I will remember to keep about 4 inches from the ends of the boards.

    You say that the finish nailer didn’t work for face nailng the areas that could be reached with the flooring nailer? I have a Paslode 16ga. finish nailer to try. It will drive a 2 1/2 in finish nail into oak but maybe the cherry might be too much for it. Anyway, thanks for the info

  11. Stevish Says:

    The finish nailer did work, but several of the nails crumpled and left large shallow holes for us to fill… we had to make some of the holes deeper so they’d hold the filler. It’s more of an annoyance than a problem, really.

  12. yogefrommuskogi Says:

    I have the skuzziest carpet because I live with two pigs disguised as humans. So…..I have been wanting to get new carpet, and today I just snapped and ripped up a big ass staied piece of rug, and under it is rotted out wet particle board. It is funny that this is the first article i opened after doing a search for how to rip out particle board flooring. I was thinking the whole time as I scraped some of the board up and found that there are beautiful hardwood floorboards under this pile of layerd shit. It is so thick that after I tear it up my husband will come home and think i raised the ceiling. Why would someone do this? As a torture treatmnet or a really sick joke? It is hard to figure, Then the ahole goes nail crazy and nails the shit down with flat head galvanized nails about three inches apart. He mustve been hammered. I love what you wrote, and now i don’t feel so lame as to how long it is taking me to rip it up. what is the best way to get the nails out. I have no idea about building and woodwork, except that particle board blows.

  13. Bettie Says:

    Has anyone figured out how to level mushy particle board which extends under the walls. ie. manufactured home. It seems the outside wall and the floor edge have water damage. Is there a strong subfloor, thin, to put over the mush and level it with the rest of the floor. My husband is ballistic because I ripped out the cabinets to put in new ones and have discovered this. I’m a DIY’er.

  14. Teresa Says:

    Hi Stevish, I googled up ‘how to remove particle board subflooring’ and your blog/article came up first on the list. I loved your writing, very humorous yet educational at the same time. Of course the article and the replies have me now terrified of dealing with my particle board subflooring LoL but at least I won’t be alone in the world of ‘dust & glue’ somehow equals wood.. – Teresa from Michigan

  15. Marika Says:

    I just did this for our entryway. A trick I learned was to make sure your prybar is sharp when working it under the particleboard. It made a HUGE difference for me.

  16. Alex Says:

    Anyone ever get so desperate they just cut the plywood subfloor with the particle board on top of it and replaced the whole thing?

  17. Debbie Roach Says:

    This may sound stupid but if water is considered an enemy of particle board would water not soften it up enough to take it out even more easily with a roofers’ shovel?

  18. Stevish Says:


    I would think you’d risk softening the subfloor underneath (especially if it’s OSB) and tearing through that with your shovel.

  19. Gerben Says:

    I got the same problem over here.. In my case the OSB is glued to concrete. Now all the wood is gone but I’m left with soft concrete with loads of glue residue. When removing glue you tear concrete of as well.

    Any ideas on how to remove the glue? The only thing that works is a rotary hammer but it takes more then an hour to remove a few feet.

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