Mdf and Plywood : The Difference
MDF and plywood are two of the most common building materials these days, especially for DIY projects. While both have their strengths, they’re not interchangeable. Know the difference when you’re comparing MDF vs plywood?
Medium density fiber board (MDF) is a homogenous mix of wood fibers and urea formaldehyde resin. It has smooth edges and surfaces, creating the appearance of one solid piece of material.
MDF has a hard surface, making it useful for some structural applications but it’s primarily used indoors due to a lack of moisture resistance. If left totally in treated MDF will soak up water like a sponge and swell, loosing it structural integrity in the process.
MDF covers a range of wood composites, but most of them have roughly the same properties. When choosing your grade you should match it to you intended application. The following are some of the varieties of MDF you’re likely to come across:
- Moisture Resistant MDF- Used in areas like bathrooms where moisture is a constant risk. It can also be used in kitchens. There are some caveats to what you can get away with, which I’ll cover in a moment. These boards are often green in colour.
- Fire Retardant MDF- An MDF variant with higher resistance to flames and heat, but definitely not fireproof. Often used for structural indoor elements such as partition walls where the extra safety is quite welcome. It’s most often red in color.
- Ultra-Light MDF- A newer variant of MDF which is roughly 30% lighter than the standard stuff. It’s great for components that need things like slots or molding but isn’t as suitable for structural applications.
MDF is bound together with urea-formaldehyde based resin. Unfortunately, formaldehyde is a carcinogen and can be irritating to the mouth and nose.
Uses of MDF
MDF has found a lot of use in the modern world. It’s a go-to material when something small and sturdy needs to be made.
Speaker enclosures, for instance, are made with MDF being covered with carpet. It’s also a go-to material for cheap furniture and cabinets. It holds up well over time provided that it’s not exposed to too much moisture.
Furniture is another common use for MDF. If you’ve ever had a low-cost, seemingly wood piece of furniture then you probably had MDF. It doesn’t have the beauty of natural wood, but it’s often used as a frame in handmade upholstered furniture such as couches.
MDF does take paint well, so it’s still used in tables and other solid pieces of furniture as well. Paint can also form a protective coating, MDF is very vulnerable to moisture unless you’re using a moisture-resistant variety. Since MDF is naturally fire-resistant it can also be used for architectural components indoors. Providing an extra barrier of protection in case of a flaming emergency. It’s still best to spend the extra on fire-resistant MDF if that’s your end game.
One thing that not many people know: MDF is good for sound proofing is as well. It’s mainly used for smaller indoor applications since drywall is often more cost-effective, but it’s a good use of the material.
There are also a couple of specialty MDF products for specific uses-
These MDF panels are fastened to look like they have a tongue-and-groove configuration. Beadboard is a decorative element, often used for things like half-wall covers for the striking texture.
Slatwall- Slatwall is often used in store displays. It comes preconfigured to accept shelving and brackets with the right fastener. Its use around the home is limited but some people use it as a storage solution in garages or kitchens.
MDF’s lack of water resistance is problematic for many uses. Non-moisture-resistant MDF shouldn’t be used in areas with high humidity, as it will soak up water from air without needing to be splashed.
Despite this, MDF is often used to create consumer-grade bathroom and kitchen cabinets. The material is usually coated with a thin wood veneer, keeping water out and providing a more natural look to the cabinets.
Strength, Durability, and Weight of MDF
MDF is quite strong, but it’s not a wonder material in that category. There are some quirks to its strength that shouldn’t be overlooked when planning a project.
One of the biggest things you need to consider: MDF doesn’t like screws. When you screw into MDF you tear apart the fibres and the screw acts like a wedge causing the MDF to split if you’re unlucky. You can get around this to a degree by drilling a pilot hole that is 85%-90% of the screw’s size. Alternatively, you can join a piece with a trim nailer, which will push the nail through the MDF. For that reason, you should reinforce most MDF projects with good wood glue, in addition to the fasteners.
MDF is also fairly easy to damage. It will crack under impact or warp under strain more easily than plywood. It’s lower elasticity means that too much loading can warp the board, which won’t return to normal afterward.
Barring issues with moisture or physical impact, MDF is a long-lasting material. It’s resistant to termites and dry rot as well, which are two long term threats to any wood.
The big advantage of MDF remains in its uniform consistency. That allows it to be worked in ways that other engineered woods can’t.
MDF is a great material to work with, as long as you’re not dealing with nails or screws. The fact is a homogenous solid piece allows it to be machined in a way that other engineered woods can’t.
It’s a good material for decorative use, as long as you aren’t going to miss the natural wood grain. Since it’s so uniform, a router is an excellent way to work with it.
As a general rule, MDF is one of the cheaper engineered composite wood products. The cost can go up with quality, but it remains a low-cost option in many cases.
When compared to solid wood, MDF is always going to be a winner on costs. MDF is generally cheaper than plywood too.
The only common wood which is cheaper than MDF is particle board. But MDF is stronger than particle board and is far more versatile.
ADVANTAGES AND DISADVANTAGES OG MDF
Due to its unique construction, MDF is a standout material for many uses. Let’s recap the main pros and cons of MDF.
- Cheaper than most composite woods
- Easy to produce good finish
- Takes paint very well
- Better for precision work due to uniformity
- Strong enough to work for cabinets and other minor structural use
- Excellent for painted furniture
- Vulnerable to water damage
- Less elasticity than plywood
- Won’t hold up outside
- Doesn’t look like natural wood
- Doesn’t hold fasteners well
MDF is best suited for smaller interior projects, where structural integrity isn’t paramount . It’s also a perfect medium for scrolled designs and other precision work, the lack of chipping allows it to hold together and cut cleanly.