If you are planning to build something out of wood, but don’t want to spend the money for real solid lumber, then two of the best choices that you have at your disposal, besides plywood, are MDF and OSB. While these are all types of engineered wood, they are all different in many regards.
With that, in this article, we will help you figure out what those differences are and, by extension, which of the two are the better material for your project.
MDF and OSB: The Basics
Before we get into talking about the similarities and differences of MDF and OSB, let’s first figure out what both of them actually are.
What is MDF?
MDF stands for medium-density fiberboard and this is a special kind of engineered wood product that is made by taking old palm tree oil extracts, wood fibers, and other wood-related products, and then pressing them together using a combination of resin and wax. MDF takes on a very smooth appearance, is quite lightweight, and is a low-cost building material of choice for various types of furniture, cabinets, and more.
What is OSB?
OSB stands for oriented strand board and this is a special type of engineered wood product that is made by taking wooden strips from very fast-growing trees, placing them in a cross-orienting manner, and then pressing them together using a variety of adhesives. OSB has become a low-cost building material of choice, especially when it comes to replacing plywood, as OSB does have more shear strength than plywood, and is therefore often used for flooring, roofing, and even for walling.
Similarities of MDF and OSB
Now that we know what exactly both MDF and OSB are, let’s figure out what similarities they share.
#1: Both Are Types of Engineered Wood
Although they are made in slightly different ways, MDF and OSB are both specific types of engineered wood. In case you don’t know, engineered wood is any type of wood, such as MDF, OSB, plywood, or anything in between, that is made out of real wood. Now, engineered wood is of course not solid wood. It is solid wood that has been broken down in one way or another and then formed into panels or boards using a variety of adhesives, pressure, heat, and other techniques.
#2: Both Are Somewhat Eco-Friendly
Another similarity that both of these two engineered wood products share is that they are both fairly eco-friendly. OSB is usually made out of very fast-growing tree varieties that are quickly cut down. Yes, it does use solid lumber, but the trees used are generally quite sustainably harvested.
On the other hand, MDF is made with old oil palm biomass and other wood-like materials. Due to the fact that palm oil is used, it is generally said that MDF is not quite as eco-friendly as OSB, but with that being said, if MDF is made out of 100% right recycled materials, then it is absolutely more eco-friendly.
#3: Both Come in a Variety of Sizes
Another very basic similarity between these two engineered wood products is that they can both come in many different sizes that are ideal for a variety of purposes.
#4: Both Are Considerably Cost-Effective
The other similarity that both of these engineered wood products share is that they are both considered very affordable. They are both certainly much more affordable than plywood is, thus making both MDF and OSB cost-effective building materials for many different applications.
Differences Between MDF and OSB
While similarities are important, let’s jump into the differences as these are what will be the deciding factor in your choice.
#1: OSB Features Cross Orientation
One of the major differences between MDF and OSB is that OSB is made in a way that the wooden strands feature a cross-grain pattern. In other words, strands are laid together in a perpendicular manner from one layer to another, thus creating a cross-grain pattern. MDF is made out of wood fibers that are pressed together and therefore there is no such cross-grain pattern. What it really boils down to is that OSB is much better at holding onto screws than MDF is.
#2: MDF Is More Eco-Friendly Than OSB
OK, so some people are undoubtedly going to tell us that we are wrong here because MDF does use palm oil, which is of course not a good thing. But with that being said, once again, if MDF is made out of recycled materials, it is much more eco-friendly than OSB that uses real trees. Sure, OSB uses very fast-growing tree varieties that are sustainable, but they are still real trees nonetheless. Due to this, we would say that MDF is the more eco-friendly of the two.
#3: OSB Is More Expensive Than MDF
Although the price difference here is somewhat negligible as they are both much cheaper than plywood, the reality is that OSB is a bit more expensive than MDF. The price of lumber in recent years, especially throughout the COVID-19 pandemic, has gone up considerably, and because OSB is made out of real lumber, it is becoming more and more expensive as time goes on.
#4: OSB Is Stronger Than MDF
Due to the fact that OSB is made with real wood strands that are pressed together using adhesives, it ends up being much stronger than MDF which is made out of wood fibers. Remember that OSB is made out of strips of wood that are laid together using a cross-grain pattern, and that cross-grain pattern does allow for a lot of added strength. For this reason, OSB is the material of choice when it comes to structural purposes and for weight-bearing applications.
#5: OSB Is More Moisture- and Weather-Resistant
OK, so right off the bat what needs to be said here is that OSB is much more moisture and weather resistant than MDF, especially if you use the right kind of OSB that is rated for outdoor use. With that being said, certain kinds of OSB can absorb some water and may suffer from some swelling, especially at the edges. On the other hand, although not all OSB is weatherproof, no MDF is waterproof or water-resistant at all. MDF can absolutely not be used for outdoor purposes, because if it gets wet it will completely crumble into bits.
#6: OSB Is Heavier Than MDF
One reason why people like working with MDF is due to the fact that it is fairly lightweight, especially when compared to OSB. In terms of engineered wood products, OSB is actually one of the heaviest ones around and this can make it somewhat difficult to work with, especially if you are working alone.
#7: MDF Has a Smoother Overall Appearance
Something else that needs to be considered here is that MDF is much smoother than OSB. Due to the fact that OSB is made with wooden strands, you can actually see that texture in the finished product. On the other hand, MDF looks completely smooth, especially after it has been painted. So while OSB may resemble real wood, MDF still generally looks a lot better in terms of aesthetics, which is why most people would choose MDF over OSB for interior purposes and for furniture. MDF just looks smoother and sleeker than OSB.
#8: MDF Is Easier to Sand and Paint
Yet another difference between these two engineered wood products is that MDF is much easier to sand and paint than OSB. All of those wooden strands can really get in the way of sanding, and they also create a texture under the paint that does not often look very nice.
#9: MDF Can Be Cut Cleaner
While both OSB and MDF are fairly easy to cut, due to the fact that MDF is much smoother, it does tend to result in a much cleaner cut than when you are sawing OSB. The edges of cuts on OSB often end up being rough.
#10: Their Applications Are Different
The simple reality here is that MDF and OSB have greatly different applications. OSB is best used as a cost-effective flooring or sub-flooring option. OSB also works well for roof sheathing and for furniture.
On the other hand, due to the fact that MDF usually needs an extra outer layer, it is best used for the making of light furniture, speaker boxes, cabinets, and low-cost flooring. MDF can also be used to build temporary structures that are not intended to be outdoors. That said, if you get the right kind of OSB, it can be used outdoors.
For more details, read my article about the common uses of OSB.
#11: MDF Is Easier to Damage with a Hammer
OSB is very impact resistant and hitting it with a hammer won’t do much, but on the other hand, MDF is not all that impact-resistant and if you hit it with a hammer you will damage it.
#12: MDF Is Made with Fibers, OSB with Strands
The other difference to consider here is that MDF is made with very small wood fibers, whereas OSB is made with larger wooden strands.
OSB vs. MDF: Which of the Two Should You Use?
Which one of these two materials that you use really depends on your intended purpose. If you are planning to make some low-cost, lightweight, and good-looking furniture and cabinets, then MDF is the way to go. However, if your project involves moisture, is exposed to the outdoors, or needs to bear weight, then OSB is the material of choice.
As you can see, both MDF and OSB are great building materials for specific purposes, but they don’t at all have the same qualities, so choosing the right one will directly affect the overall outcome and quality of the final project.