Removing glued down particle board from subfloor

Question

I'm in the middle of replacing some old carpet in my house with engineered hardwood boards. They're tongue and groove and I'll be nailing the boards down in the end. To that end, I had to remove the particle board layer covering my plywood subfloor.

After starting on the particle board removal, I found them to be glued down, in addition to the visible nails. I've gotten all the boards up, but now I'm left with patches where the glue lines were down.

On one side of the room the subfloor ply is hard enough that I was able to chisel up the lines and it's all relatively flat now. On the other, however, the boards are much softer and as such tend to splinter and tear up when trying to get the glue piles up.

Is there any technique to do this effectively? I've also tried sanding the areas down, but it's hard to keep it from hitting the subfloor and is very slow work.

Answer 1

You will need to get a Razor floor scraper.

It takes a little practice to get the angle that you hold it at in relation to the floor.

Do not be to aggressive until you get a feel for how well it is removing the glue. Do not go straight at it, angle the blade to patch and gently poke or prod at it, this will result in you getting a little further under it with each poke. Maintain the, just right, angle and keep working at it.

The glue is strong and you are going to gouge some of plywood but try to minimize this, you can patch later. You may have to come at it from another direction.

It is not fun, it is hard work. Some floor scrapers work better than others, buy extra blades.

Answer 2

I like the razor scraper idea. So far I have been using a hammer drill to quickly pull the non-glued parts of the particle board. Then I get a small putty knife and drive under other loose parts (easier than doing the same with a pry bar). I then “rake” the glued down parts with the hammer drill (wide chisel tip), which lowers the height of the remaining particle board. Invariably I cause minor damage to the plywood subfloor. Finally I sand the last bits with a belt sander, loaded with a 40 grit belt. This is unpleasant. A real floor sander would work faster but probably damage the subfloor more. This job sucks, and I can’t claim to have a silver bullet, but this is my experience fwiw