Lately, I’ve had several people ask me questions about MDF.  What is MDF?  How is it different from plywood?  Why wouldn’t you just use plywood?

So today I want to share the differences between MDF and plywood, the pros and cons of each, and how I decide which one I’ll use on a project.

MDF – Medium Density Fiberboard

MDF is an engineered wood composite that is similar to particle board, but is much denser and stronger than particle board.

Imagine if all of the sawdust was swept up from other wood product manufacturing processes, and then that sawdust was mixed with binders and pressed into large sheets the size of plywood.  Okay, that’s way oversimplified, and it’s not exactly the process they use to make MDF 😀 , but that gives you an idea of the makeup of the product.

Because it’s composed of such small wood fibers, there’s no wood grain in MDF.  And because it’s pressed so hard at such high temperatures, there are no voids in MDF like you find in particle board.  Here you can see the visible difference between particle board and MDF, with MDF on the top and particle board on the bottom.

Just like plywood, you can purchase MDF in different thicknesses depending on what you need for your project.

Advantages of MDF

• MDF is generally cheaper than plywood.
• The surface of MDF is very smooth, and you don’t have to worry about knots on the surface.
• Because it’s so smooth, it’s a great surface for painting. I recommend first priming with a quality oil-based primer.  (Don’t use aerosol spray primers on MDF!!  It just soaks right in, and is a huge waste of time and money.  It will also cause the surface to become rough.)
• Also because of its smoothness, MDF is a great substrate for veneer.
• MDF is very consistent throughout, so cut edges appear smooth and won’t have voids or splinters.
• Because of the smooth edges, you can use a router to create decorative edges.
• The consistency and smoothness of MDF allows for easy cutting of detailed designs (such as scrolled or scalloped designs) using a scroll saw, band saw, or jigsaw.

Disadvantages of MDF

• MDF is basically glorified particle board.
• Just like particle board, MDF will soak up water and other liquids like a sponge and swell unless it’s very well sealed on all sides and edges with primer, paint, or another sealing product.  Again, I recommend a quality oil-based primer.  No aerosol spray primers!!
• Because it consists of such fine particles, MDF doesn’t hold screws very well, and it’s very easy to strip the screw holes.
• Because it’s so dense, MDF is very heavy.  This can make it more difficult to work with, especially if you don’t have a helper who can help you lift and cut the large sheets.
• MDF can’t be stained.  Not only does it soak up stain like a sponge, but also because there’s no wood grain on MDF, it looks awful when it’s stained.  (Kind of like staining particle board.  Why would you bother?)
• MDF contains VOCs (urea-formaldehyde).  Off gassing can be greatly minimized (but probably not eliminated) if the MDF is encapsulated with primer, paint, etc., but care needs to be taken while cutting and sanding to avoid inhalation of the particles.  I recommend cutting and sanding outside while wearing a particle mask.

Plywood

Plywood is also an engineered wood product that is made by pressing and binding sheets of wood veneer together into one solid piece.

Plywood comes not only in different thicknesses, but also in different grades, so you can choose the right one for your project.  Lower grades are used in construction of houses for subfloors and such.  Obviously these types of plywood don’t need to look pretty since they’ll be covered up.

The higher grades of plywood (stain grade, cabinet grade, etc.) are much prettier and smoother.  They have consistent wood grain showing, and generally lack knot holes or other major imperfections.  And cabinet grade plywood is always sanded very smoothly on the surface.

You can also find plywoods in various wood species, like oak, or maple, or pretty much anything else, so that you can get exact look you want for your project.

Advantages of plywood

• Because it consists of layers of wood veneer with the grain on each layer running a different direction, it’s a very strong building material.
• It’s less susceptible to water damage than MDF, and won’t soak up water and swell as quickly or easily as MDF does.
• It’s stainable, which makes it perfect for kitchen cabinets, table tops, and other projects where you want a large stained wood surface.
• It holds screws very tightly since the varying grains of wood on each layer give the screws something to hold onto.
• While most plywood does contain urea-formaldehyde and other VOCs, it is now possible to purchase plywood without formaldehyde.  Look for the Purebond brand at Home Depot.

Disadvantages of plywood

• It’s more expensive than MDF.  And obviously, the higher the grade, and the more special the species of wood, the more expensive it gets.
• Because of the layers that show on the edge, you have to finish off the edges somehow.  This can be done with iron-on edge banding or with pieces of lumber or decorative molding.
• Plywood will often splinter on the edges when cut, so it’s harder to get a smooth cut with plywood than it is with MDF.
• It’s more difficult to cut detailed designs into plywood (scrolled, scalloped, etc.) because the edges will splinter, and then you’re left with edges that show layers and might possibly have voids in some places.
• Like MDF, most plywoods contain urea-formaldehyde and other VOCs which can off-gas into your home.  Take precautions while cutting.

How I determine which one to use:

Actually, we’re going to do this “pop quiz” style.  Are you ready? Don’t be nervous!  There will be no failing grades handed out in this class.  🙂

1.  Scalloped console table

For this project, I needed something that I could use my jigsaw on to cut out a detailed, scalloped design.  I needed the entire thing — surfaces as well as all cut edges — to sand perfectly smooth.  I knew I’d be painting the table (or covering it somehow), so staining wasn’t a consideration.

So which one would I use for this?  Plywood or MDF?

2.  The bottom shelf on my coffee table ottoman.

I obviously needed a large, smooth surface for the shelf, but the main consideration here was that it needed something that could be stained to match the other wood components of the coffee table base.

So which one would I use for this?  Plywood or MDF?

3.  Scalloped decorative mirror

I needed to use something in which I could cut a detailed, scalloped design and be left with smooth edges.  I knew I would paint this piece, so staining wasn’t an issue.

So which one would I use for this?  Plywood or MDF?

4.  The upper bookshelves on my built-in bookcase wall

I needed something strong for building.  Since I would be painting the whole thing, staining wasn’t a consideration.  I also knew that I would be covering up all of the edges with trim, so that wasn’t a consideration either.

So which one would I use for this?  Plywood or MDF?

Answers:

Are you ready to see how you did on your quiz?  😀

1.  For the scalloped console table, I used MDF.  It’s paintable and smooth.  The smooth edges allow for detailed, scrolled designs to be cut.  And the edges sand smoothly as well.

2.  For the lower shelf on the ottoman, I used plywood.  Plywood is stainable, where MDF is not.  I covered the not-so-pretty edges with pieces of 1″ x 3″ lumber.

3.  For the scalloped mirror, I used MDF, for all of the same reasons as on the scalloped console table.  (FYI, this also could have been made out of 1″ x 4″ lumber, cut into four pieces and mitered in the corners to make a frame.  Then the scrolled design cut on the inside edge of that frame.  The benefit of the MDF is that there are no mitered corner seams, and no extra work piecing together a frame.)

4.  This was a trick question.  🙂  I actually used MDF on this project, but plywood would have been perfectly acceptable, and actually it would have been preferable.  If I had been building bookshelves that sat on the floor, where the edges might be susceptible to spilled water or even floods from plumbing issues, I would have definitely used plywood.  However, with these being just on the top, away from the floor, I used MDF to save money.

So how did you do?

If you have any questions regarding MDF vs. plywood, I’d be happy to answer them for you if I can!

Addicted 2 Decorating is where I share my DIY and decorating journey as I remodel and decorate the 1948 fixer upper that my husband, Matt, and I bought in 2013. Matt has M.S. and is unable to do physical work, so I do the majority of the work on the house by myself. You can learn more about me here.