There are many options of materials you can choose from when building a shelf. Timber, plywood, chipboard, and glass are among the choices of materials that can be used and made into a shelf. Among the materials, MDF is one of the popular choices to use. But you might be wondering, is MDF good for shelves?
MDF is a good material for making shelves because it’s cheaper than plywood, it’s strong enough to carry light to medium loads, it’s easy to cut to size, has a smooth surface, and paint applies well to it. Additional stiffeners and supports can be added to the MDF shelves to allow for heavier loads.
Just like any material, using MDF for shelves has some advantages and disadvantages. It would be helpful to know some of these so that you would know how best to approach any shelving project you are planning to do.
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What Do You Need To Consider Before Building an MDF Shelf?
There are a few things to consider when using MDF for shelving. Among these are its ability to carry weight, how wide you can span it without sagging, and the thickness you should use for shelves. We’ll talk more about these below.
1. Is MDF Strong Enough for Shelves?
For light to medium loads such as vases, trinkets, books, and small plants, a 3/4″ (18mm) thick x 12″ (300mm) deep MDF shelf built normally is strong enough to support these. For heavier loads, with additional support, or reinforcement, an MDF shelf will be strong enough to carry these as well.
In most cases, MDF will work well as a shelf for any load requirements. Its strength will all depend on the manner it was built, the thickness of the MDF used, the reinforcements placed to the MDF, the number and spacing of the supports, and for which general area will it be used for.
Also, MDF should only be used indoors, and generally away from high-moisture areas. Because of the components MDF is made out of, it acts like a sponge when it gets exposed to water or any high moisture environment. Moisture will degrade it’s strength significantly. As long as you keep it away from water or any liquid, your MDF shelves will remain strong.
2. How Much Weight Can an MDF Shelf Hold?
According to thisoldhouse.com, an MDF shelf with a size of 3ft. (900mm) long x 1″ (25mm) thick x 12″ (300mm) deep and unsupported can hold 87 lbs. (40kg) of weight without sagging more than 1/4″ (6mm). Comparing it to other shelf materials with the same dimensions and conditions, oak can hold 313 lbs. (140 kg), pine can hold 200 lbs. (90 kg), and plywood can hold 129 lbs. (58 kg).
Most of the other shelving materials can carry heavier weights compared to MDF but you can always add supports and reinforcements to the MDF shelf to allow it to carry heavier loads as discussed above.
One of the biggest consideration why some still chooses and uses MDF for shelves in spite of the strength discrepancy with the other shelving materials is the cost. MDF is way cheaper than the solid woods and most plywood grades.
3. How Far Can an MDF Shelf Span Without Sagging?
A 3/4″ (18mm) thick MDF shelf supported only at its end can have a span of 28″ (710mm) for light loads, 30″ (760mm) for medium loads, and 24″ (600mm) for heavier loads without sagging for more than 1/8″.
For reference, light loads is considered as small objects, vases, small plants, etc. Medium loads is considered to be a set of paperback books. Heavy loads is considered to be large hardcover books, tools, etc.
If you want help determining how wide the span of MDF shelf you can use for your project, you can try out the sagulator by woodbin.com. It will help you determine how wide a span you can use for MDF shelves with an acceptable sagging, and for a specific weight.
4. How Do You Prevent MDF Shelves From Sagging?
MDF shelves will sag depending on the weight it is carrying and the type of reinforcement and support brackets it has. Heavier loads will tend to bow and sag MDF shelves more but a good reinforcement or support attached to it will stop the sagging.
The general idea with regards to preventing MDF shelves from sagging is to support its underside with a sturdier, and more rigid material that will not bow or flex as much as MDF. You can also use any material as well such as solid wood or metal as long as it is rigid and will not flex with the MDF and the weight applied to it.
There are virtually different ways of supporting an MDF shelf to prevent it from sagging, and you can literally design them in any unique way you want as long as, again, the supports are sturdy and rigid.
Here’s a list of some of the common ways you can prevent MDF shelves from sagging.
A. Add Continuous Strips of Reinforcement Underneath the MDF Shelf
You can add a continuous strip or several strips of reinforcement underneath the MDF shelf. The strips can be made from wood or steel, but this will depend on the final look you are after. Most people tend to use wood more because of the look, the cost, and the ease of creating the strip. A steel strip would be more rigid and sturdier, and it can still look good in certain design themes.
The strips can be placed anywhere underneath but commonly, it is placed at the back against the backer board, at the front as a nosing or trim, or in both locations. You can also add a strip support midway between the front and back of the MDF shelf.
Below are images showing options of where you can place the continuous strips of reinforcement underneath the MDF shelf.
B. Use a Thicker MDF Sheet for Shelving
A thicker MDF board used for shelving will sag less than a thinner MDF. You can also span it wider than the thinner MDF shelf.
Normally, MDF used for shelving are 3/4″ (18mm) thick. You can try using a 1″ (25mm) thick MDF board instead. This will, however, be more expensive, and heavier to work with than the 3/4″ (18mm) thick MDF boards.
C. Build Fixed MDF Shelves Instead of Adjustable MDF Shelving
There are MDF shelving units that are built with adjustable pins so that you have the option to adjust the heights and spacing of the shelves. This, however, will sag more than fixed shelves because of the lack of anchoring at the ends.
If you want to prevent the MDF shelves from sagging, it would be better to fix and anchor the shelves to the back and the sides. You can use brad nails or screws spaced at 5-10 inches (125mm – 250mm), and with wood glue for better adhesion.
D. iNSERT the MDF Shelf to a cUT Dado at the BackER bOARD
Inserting and attaching the MDF shelf to a dado at the backer board will help support the shelf and prevent if from sagging. The dado will act like a continuous strip of reinforcement you’ve placed at the back side of the shelf. The deeper the dado, the better support the MDF shelf will get.
E. Use Shelf Brackets Spaced Appropriately Underneath the MDF Shelf
Shelf brackets come in different shapes, sizes, styles, and designs. You can purchase them from any hardware store or just create your own from scratch. Common shelf brackets are made out of wood or steel.
With using shelf brackets to support your MDF shelf, the important thing to remember here is to space them out appropriately. Depending on the weight that the MDF shelf will carry, you can space them out wider or closer together. The heavier the weight your MDF shelf will carry, the closer the shelf brackets should be spaced from one another.
Rule of thumb for the spacing of shelf brackets for 3/4″ (18mm) thick MDF shelf is to space them no more than 20″ (500mm) apart for medium and heavy loads and 28″ (710mm) for lighter loads. Thicker 1″ (25mm) MDF shelves, can have the brackets space at 28″ (710m) for medium and heavy loads.
The different spacing above is just a guide and you can always adjust them depending on the weight your MDF shelf will be carrying.
F. Create a Torsion Box
For deeper MDF shelves, such as 14″ (350mm) or more, you can build a torsion box to prevent the shelf from sagging. A torsion box is basically a grid of supports you place underneath the shelf to prevent it from sagging in any direction. It is normally made out of wood but you can also use steel to create one.
A torsion box is normally created for floating shelves but you can also use it for shelves supported at the ends.
Creating a torsion box will be more expensive though and the cost of creating this will offset the savings of using an MDF for shelving. You might be better off using plywood or hardwood instead. But then depending on the shelf design you’re after, MDF with torsion box support design might still be better for you.
Below is a video showing how to create a torsion box for a deep floating shelf. The shelf in the video is made of plywood though but you can always substitute the plywood for MDF boards.
Here’s a video explaining some of the ways of preventing a sagging shelf that was discussed above.
5. How Thick Should MDF Shelves Be?
Commonly, 3/4″ (18mm) thick MDF sheets are used for shelving. Don’t use MDF sheets that are thinner than 3/4″ (18mm) for shelves because they will sag a lot easier. You can use sheets that are thicker than 3/4″ (18mm) like 1″ (25mm) but workability with the MDF will be a lot harder.
6. What Are the Advantages and Disadvantages of Using MDF for Shelving?
Below is a list of advantages and disadvantages of using MDF for shelving. This can help you further decide if using MDF for shelving is appropriate for your project.
A. Advantages of Using MDF for Shelving
- MDF is a lot cheaper than the other shelving materials, so if you have a limited budget, MDF is a good option for shelves.
- MDF has a smooth surface and requires less time to prepare for painting than other materials such as plywood.
- MDF is easy to cut, even along the edges. It will not tear or splinter, and it creates a very clean edge when cut.
- MDF takes paint very well.
- You can create a very nice edging in MDF using a router.
- It is very flat, even compared to high grade plywood sheets.
B. Disadvantages of Using MDF for Shelving
- The edges and corners of MDF boards are easy to crush and damage. When working with MDF sheets, you should really be careful not to bump anything hard on its edges.
- MDF boards and sheets are denser than most wood products which make it heavier. Working with this material might become a challenge, especially if you’re doing this by yourself.
- MDF is more sensitive to water and moisture than other wood products. It will swell, warp and distort when it gets wet, damaging it and making it unusable for shelves.
- MDF can’t be stained. And there’s nothing to show if you stain it anyway, unlike other wood products with beautiful grain patterns showing on the surface.
- MDF can only be used indoors. Because of its sensitivity to moisture, you should avoid exposing it to areas that get exposed to water or liquids.
- MDF produces a lot of fine dust when cutting, sanding, or routing.
7 Tips on Using MDF for Shelves
1. Use Power Nailers When Working With MDF
MDF sheets can be rock-hard and it will be difficult to manually hammer nails into them. You could even bend the nails when using a hammer on MDF. It would be better to use power nailers to attach MDF together because of the ease and speed it offers.
2. Avoid Rough Handling the MDF Sheets
The edges and corners of MDF sheets are easy to crush and damage. Be careful when handling these as hard objects could easily damage the edges and corners of the MDF sheets if it gets accidentally hit or bump.
3. Use the Sagulator By Woodbin.com
Use the sagulator by woodbin.com to help you determine the appropriate span for your MDF shelf with an acceptable sagging and to carry a specific load or weight. This tool has helped a lot of DIYers of their shelf projects, even when using a different shelf material other than MDF.
4. Make Drill Holes Into MDF Before You Drive the Screws
When using screws to attach MDF, drill a hole first, roughly 80% diameter of the screw diameter, before you drive the screw in. Since MDF is a very dense material, forcing a screw into it can split and damage the sheet.
5. Cut and Route the MDF Outside
MDF will produce very fine dust particles when you cut it or route it. The dust particles also tend to linger a lot longer in the air than dust particles from other wood products. It will be best to do the cutting and routing outside to manage the dust from the MDF sheets better.
6. Wear Mask and Goggles When Working With MDF
Since MDF produces a lot of fine dust particles, it is advisable to wear mask and goggles to prevent you from inhaling the dust particles or getting some into your eyes. This is especially important when your cutting or routing your MDF sheets.
7. Purchase Smaller Sections of MDF Sheets for Easier Handling
MDF sheets can weigh a lot and it’s going to be a challenge handling the sheets by yourself. If you can, avoid buying the full MDF sheets. Some lumberyards and home centers sell half sheets (4 x 4 ft) or quarter sheets (2 x 4 ft). These sizes will be easier to handle and carry especially if you’re doing the project on your own.