Particle Board, or chipboard, was widely used as an underlayment for carpet in the 1970s and 1980s. It was often used to raise the height of the carpet to match hardwood and tile installations in the house. More and more people are now encountering this when they purchase older homes and decide to modernize them with new flooring.
If you’re planning to install hardwoods and you’ve discovered that there’s a layer of particle board underlayment on top of your subfloor, then you’re probably wondering if it can stay or if it must go.
Should You Install Hardwood Flooring Over Particle Board?
Do not fasten hardwoods to particle board. Particle board is made of wood chips that are glued together, which readily absorb moisture and will not hold nails or staples. This makes it unsuitable for fastening hardwoods. Installing hardwoods on particle board may also void the warranty.
What is Particle Board and How is it Made?
To really understand why particle board is an entirely unsuitable material to nail, staple, or glue hardwoods to, it helps to know a little bit about particle board itself first. I won’t go too deep, but I want to give you a brief overview of what exactly particle board is first.
What is Particle Board?
Particle board, also known as chipboard and low-density fibre board (LDF), is a wood product that is made using wood waste such as wood chips, sawdust, and shavings from sawmills. Particle board is often used when cost, rather than strength, is the primary factor.
These materials are mixed with glue, or resin, and formed into sheets. The sheets are then compressed to reduce the thickness and then heated and compressed again to cure the glue.
If you look at the cross section, you’ll see that it looks sort of like oatmeal.
Does Particle Board Absorb Moisture?
Particle board absorbs moisture very easily and this is one of its main weaknesses when used under hardwood flooring. When the fibers get wet, they swell causing damage to the particle board. If not dried out immediately, this can lead to deterioration requiring extensive repairs to the floor.
I took the photo above while working on replacing some old laminate flooring that had been floated on top of a particle board underlayment. This was in a hallway near the kitchen.
The refrigerator had leaked at some point in the past and soaked into the underlayment. You can see where the homeowner had attempted to repair part of it by replacing the particle board with plywood. Why they didn’t repair the entire section is beyond me, but maybe for the best since it was a poor attempt at repair.
Here’s what I found when I ripped up the particle board. You can see that the subfloor under the particle board was completely rotted out.
Just to drive the point home about just how well particle board absorbs moisture, here’s one more photo. In this photo, the particle board bas been pulled up, but you can see the water damage to both the particle board and the subfloor below.
This section of subfloor had to be cut out and replaced.
Can You Nail Hardwood Floors to Particle Board?
If you are going to nail or staple your hardwoods down, then you absolutely must remove the particle board first. Never nail or staple hardwood floors to particle board. There are several reasons for this, not the least of which is that particle board is not suitable as a structural subfloor.
Other good reasons to take this advice include:
- Particle Board will not hold nails or staples. It may hold them for a while, but likely not very long, and certainly not permanently. Look above at the photo of the cross-section again. You can see that there’s really nothing there for the nails to hold on to. It’s lacking the fibers of plywood since it’s essentially just sawdust and glue.
- What about long nails? The thinking here is that you can use long flooring cleats and penetrate far enough through the particle board and into the subfloor. The problem is that the cleat passes at an angle through the plank of hardwood, then the particle board, and finally into the subfloor. There simply will not be enough in the subfloor to hold properly.
- Particle Board is Brittle. Besides the fact that particle board simply won’t hold nails or staples well, it’s also brittle. This means that movement of the floor can cause the cleats to break bits of the particle board up, causing the floor to become less stable.
- It may void your floor’s warranty! Of all the reasons given, this may be the most important one to consider. All hardwood installation guides list what is considered suitable underlayment materials. Not only that, but some explicitly prohibit fastening to particle board. If you don’t install your floor according to the manufacturer’s guidelines, you may very well void the warranty on those expensive hardwoods you bought.
There is really no good reason to nail hardwood floors to particle board. If you plan to nail down your floors, then check out the section below on removing particle board. This is going to be your first step.
Can You Glue Hardwood Flooring to Particle Board?
No, you should not glue hardwood floors to a particle board. The main concern with glue and particle board is that any excess moisture can cause particle board to swell and fall apart. This will destroy the bond between the hardwood floor and the hardwood floor glue. Remove the particle board first.
Moisture isn’t the only concern. Many of the concerns listed in the section above apply here as well. Simply put, particle board is not suitable for any sort of installation that involves fastening the hardwoods to the subfloor. And please remember to always check the warranty conditions for your flooring.
Is it Ok to Float Hardwoods over Particle Board?
If you are planning to install engineered hardwood floors and absolutely do not want to deal with removing the particle board underlayment then you can get away with a floating floor installation if it will not void your warranty. You should never float solid hardwoods over particle board.
The reason I singled out engineered hardwoods above, is that you would typically never install solid hardwoods using the floating floor method. Even if you did, solid hardwoods are more susceptible to moisture. And given how easily particle board absorbs and holds moisture, this is a recipe for disaster.
Engineered hardwoods are more dimensionally stable than solid hardwoods and stand up better to changes in moisture. I covered whether or not they can get wet in this article if you’re interested.
However, you still need to protect them from moisture, especially if you’re installing over particle board. You’ll need to use a good moisture vapor retarder such as Aquabar B or maybe something even more waterproof. You’ll need to check with your flooring’s manufacturer for specific guidelines to ensure you stay within the terms of your warranty.
All of that said, I still do not recommend any type of hardwood install over particle board.
How to Remove Particle Board From the Subfloor
Hopefully by now I’ve convinced you that you really should not install your expensive new hardwood flooring over that old, nasty particle board underlayment. It’s a terrible idea for all of the reasons I listed above, but chances are, if you have particle board under your carpet, it has been there for years.
Just imagine how many foul liquids have been spilled on that particle board over the years. When I ripped up the laminate flooring in my house, the smell of the particle board was terrible. And no wonder why – just scroll up and check out those photos of the water damage again.
So how can you remove it other than paying someone to do it? There are a few options:
Cut and Pry
Particle board underlayment is typically installed in 4 ft x 8 ft sheets. The goal of this method, which I’ve dubbed the “cut and pry” method, is to cut into smaller pieces. This can make it easier to remove the particle board without it breaking into many small pieces.
As I mentioned in a previous section, particle board is very brittle. Once you start prying it up, you will often break off small pieces. This is not only frustrating, but leads to a bigger mess to clean up.
Ok, so here are the basics of the “cut and pry” method. You will need the following tools:
- Safety glasses
- Ear protection
- Dust mask/respirator (this will create a lot of dust)
- Work Gloves
- Footwear suitable for walking around nails
- A circular saw
- A pry bar (or two)
- A hammer or Mallet
To get the particle board up:
- Put on all safety gear
- Set the saw blade depth to be just greater than the depth of the particle board. You want to cut just through it without cutting too much into the subfloor. Scoring the subfloor won’t hurt it, but do not cut deeply into it.
- Cut the sheets of particle board into smaller sections.
- Use the hammer to work the pry bar under the edge of one sheet and start prying up the pieces.
- Once you’ve cleared a section go back over the floor and pry up the nails or staples that pulled through the particle board.
- Vacuum the floor. As you run the vacuum head across the subfloor, you’ll discover even more nails and staples that you missed the first time.
That’s really all there is to it. Here’s a good video tutorial on this method:
While the cut and pry method can make it easier to get the sheets up in bigger pieces, it does have a few disadvantages.
- It produces A LOT of dust when cutting the particle board. Not only do you need a good dust mask, N95 or better, but you may also want to seal up the room you’re working in.
- Although it shouldn’t matter as long as you don’t go too deep, you will almost certainly cut into your subfloor
- It requires a circular saw. If you don’t already own one, you’ll have to borrow, buy, or rent one.
I actually prefer not cutting the particle board and simply prying up the sheets whole, or as close to whole as I can get them. Yes, some will break up, but as you can see from the video, that happens with either method.
So what’s the trick? I’ve found that the way to do this is to use two pry bars (technically a pry bar and a wrecking bar).
- One needs to have a flat head design, such as the Stanley Wonder Bar. This allows you to more easily work it under the edge of the particle board with the hammer.
- The second one is a long wrecking bar that makes it easier to pry up the board. Something like this 36″ Estwing Gooseneck Wreck Bar will do.
Here’s how it work. Oh and yes, you will want all of the same safety gear as the cut and pry method other than the earplugs.
- Work the pry bar under the edge of the particle board and lift it.
- Slide the wrecking bar under the raised section and start prying up the edge, moving away from the pry bar.
- Continue down as far as you can reach.
- Once you can reach no further, or pry no more, move the pry bar down to where the wrecking bar is now and keep prying.
- Don’t forget to remove nails or staples that are left behind, vacuum, and repeat. You will be amazed at how many nails you miss on the first, second, or even third passes.
I found this method to be extremely effective, relatively quick, and a lot less messy than cutting. As you can see in the photo below, I was able to remove most sheets whole or in large chunks.
It takes a little time, and you will have to dispose of it, but removing particle board underlayment isn’t a difficult job. Of course, if you prefer, you can simply hire it out. Either way, I hope you’ve now decided that this is the right thing to do and that you won’t be installing any hardwoods over particle board.