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What is MDF (Medium Density Fiberboard)?

By S. Mithra
Updated: May 17, 2024
Views: 131,321
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Medium density fiberboard, or MDF, is a composite wood product similar to particleboard. It's made out of wood waste fibers glued together with resin, heat, and pressure. MDF is appropriate for many applications, from cabinetry to moulding, because it is smooth, uniform, and won't warp.

MDF has many advantages over plank wood, particleboard, or high density fiberboard. It's very smooth because the wood fibers used in its manufacture are uniform and fine. This makes it have low "tear out," which means that when sawed, the end has a smooth cut instead of a jagged edge. This also means that a coat of primer and a couple of coats of paint take well, leaving an attractive, finished surface unlike other composite wood products. MDF also has a mild reaction to moisture, meaning it won't warp or swell in high-humidity applications like a bathroom cabinet.

Builders use MDF in many capacities, such as in furniture, shelving, laminate flooring, decorative moulding, and doors. They value MDF for its insular qualities in sound and heat. Also, it can be nailed, glued, screwed, stapled, or attached with dowels, making it as versatile as plank wood. Usually, people working with MDF use a carbide saw fitted with a vacuum to reduce the amount of airborne dust. Since MDF is strengthened with resin containing formaldehyde, those at exposure try to reduce their risk of inhalation, or use special MDF with lower formaldehyde levels.

Reconstituted, engineered wood products like MDF are often covered in a veneer or laminate. These thin layers of vinyl or real wood disguise the MDF, especially along visible edges. Some people prefer using MDF over regular lumber because it has a lower impact on the environment. MDF is solely made from waste products, the leftover scraps that would otherwise be dumped in a landfill. This attraction has helped it gain popularity among homeowners. It's now available not just to contractors. Many home improvement centers and lumberyards stock it in sheets for the general public.

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Discussion Comments
By roselilly13 — On Apr 16, 2015

I have a dining table with two extensions. They were in storage and have bowed in the middle when I recently took them out. Is there a method I could DIY to correct this problem?

By anon939323 — On Mar 13, 2014

So---is mdf safe or not? Too many people die of horrible cancers to not ask serious questions about such products.

By anon355485 — On Nov 17, 2013

By River1996 — On Jul 23, 2012

I just bought a little dresser, nightstand and headboard for my three year old's small room. It is made of MDF and when it arrived it was labeled formaldehyde phase 2. The smell is strong and burns my throat. One piece seemed strong but we can't use the drawers. With all three in there, the room smelled toxic.

Is this safe for a small child? Will the smell ever go away? We moved the dresser and nightstand into the living room with the drawers out.

By anon168313 — On Apr 16, 2011

@anon743: if it looks bumpy, you can sand it with a very fine wet/dry sandpaper and it will make it smooth. --LC

By anon164586 — On Apr 01, 2011

looking at water bed rails. They are made of MDF. Sleeping next to this material sounds like a not so good idea. We have a humidifier in the room. also a bad combination?

By anon164380 — On Mar 31, 2011

MDF needs to bear a prominent and clear warning about its vulnerability to water damage. I was given furniture that (unknown to me) had been sitting in a garage where a water-pipe burst in the recent cold-weather. When I hauled it to its new home, the legs had disintegrated! Water had been taken in by the fibrous board and ruined the piece of furniture.

By anon160725 — On Mar 16, 2011

MDF would warp, why? Does anyone know how to solve this problem?

By anon159201 — On Mar 10, 2011

I love MDF, it is job security in the water damage industry. Looks good and has to be replaced if it gets wet even a little wet. Ditto for particle board.

By dya — On Feb 23, 2011

Why do the wood materials need to be as thin as possible for making into wood composites?

By anon154716 — On Feb 21, 2011

The time taken to put on safety masks and gloves will likely cramp your creativity. Most people have a low immune system, and so always reach out for all kinds protective gear in any situation.

MDF brings out the artist in us. MDF was just waiting to happen, for the artistic-minded who are always groping for user-friendly, (and conservation-activists-friendly) materials. Only it is not advertised enough. Just a useful tip to counteract all fears about moisture fears: coat it (a brush will do) with clear PU coating and you seal in your fears and could even spill hot coffee over it.

By anon136613 — On Dec 23, 2010

MDF: "Friendly on the environment"? Not really. Folks, real wood will naturally decay over time into valuable nutrients for organisms on the forest floor. MDF is made using a synthetic chemical concoction including formaldehyde, a carcinogen.

All of the inappropriate chemicals introduced into the atmosphere may be the leading cause of cancers. Off-gassing of products in homes and buildings is only hitting the radar in N.America of recent time.

Plastics, formaldehyde, toxins in paint and carpeting will off-gas (mix with your indoor air) and bring a risk to you.

Be careful what you purchase and install in your living space. Think twice about MDF.

By anon135441 — On Dec 18, 2010

I have just been diagnosed with lower-respiratory lung disease, asthma, sleep apnea, rhinosinusitis, sinusitis,and am under doctors care right now.

I have to get a c-pap machine, use two inhalers, nose spray. I have been classed as totally disabled since October 2008.

I worked for Rails Plus, Inc., from denver, on a brinkmann constructors job site in broomfield,co. OSHA issued an overexposure citation. If you have been exposed to this crap, you can go to concentra medical for diagnosis and treatment, and possibly legal action as far as workers comp., and social security disability.

By anon130945 — On Nov 30, 2010

is Hardboard as dangerous as MDF when cutting it?

By anon105132 — On Aug 19, 2010

Would MDF board be suitable to make a bathroom door?

By anon100719 — On Jul 31, 2010

Yes, there are published safety concerns with MDF dust and fumes.

By anon91435 — On Jun 21, 2010

Where is this wood available? What is the cost of this wood ? On which bases they will sell this wood (i mean weight or length)

By anon88505 — On Jun 05, 2010

Please, i have recycled MDF but it is so fragile. is there any chemical that can be painted on it to strengthen it?

By anon84195 — On May 14, 2010

would i be able to make a phone holder out of one?

By anon77547 — On Apr 14, 2010

Are there special precautions for cutting MDF with a laser?

By anon73920 — On Mar 30, 2010

Just one question. Is MDF good material for glass show cases? Are they reliable and sturdy enough for glass? Thanks.

By anon73667 — On Mar 28, 2010

I recently had cabinets made in a 12x 15 upstairs bedroom for crafts and sewing. I also have recently struggled with a skin rash.

Four days ago, I left the door closed when I was out of town. The smell is so strong that I can taste it when I opened the door.

Does anyone think that the smell will die down after sealing the ends of raw MDF? Is my rash connected to this MDF?

It's a shame to have to rip out all the cabinets. I wish I had known about this earlier. Is there a warning label at Home Depot?

By anon67568 — On Feb 25, 2010

can MDF be used in a bookshelf?

By anon64955 — On Feb 10, 2010

can I use it for my woofer box?

By anon50657 — On Oct 30, 2009

MDF is garbage. It does warp if you don't store it correctly (i.e. level and straight on a rack). Water and moisture destroy it unless you take the types of steps to protect it that most people don't. It has a nasty chemical odor when you cut it that you know can't be good (formaldehyde!). This is something to be used for desperate homeowners on a budget as a short term (read: less than 20 years) remodel, or developers that are churning out McMansions for the ignorant to ogle at.

By anon47946 — On Oct 08, 2009

I love it. my whole house is made out of it.

By anon47457 — On Oct 05, 2009

it's toxic and should not be inhaled.

By anon46915 — On Sep 30, 2009

I don't think I've ever seen a more contradictory set of comments. MDF is environmentally friendly. MDF is not environmentally friendly. MDF is toxic. MDF is not toxic. MDF is better than real wood. MDF is not better than real wood. MDF warps. MDF doesn't warp. The earth is rectangular. The earth is square. I don't know what I'm talking about. Neither do I.

By anon44463 — On Sep 08, 2009

this is just awesome. :)

By anon43194 — On Aug 26, 2009

mdf is not as toxic as it is reported, it lets off the same toxic fumes as pine, because that's what it is. the urea formaldehyde only makes up 10 percent of the board; the other 90 is pine. it isn't made out of scraps as stated they specifically cut trees down to use for mdf. the worst kinds of dusts are hardwoods, i.e iroko sapele and meranti. the urea part is the adhesive, the formaldehyde is the substance which stops the adhesive setting, therefore when the resin is applied the formaldehyde evaporates and the urea sets. therefore it doesn't let off deathly quantities of toxic fumes people claim when cut. the report that the dust is the same as asbestos sharp which sticks to the walls of your lungs is rubbish as well. it's simple ignorance of the facts, just because it creates a lot of dust doesn't mean it's more toxic, but it still isn't good for you. wear ppe.

By anon42021 — On Aug 18, 2009

is mdf safe to make kids' furniture? I'm going to make the kids a bed like a car.

By jrk189 — On Aug 12, 2009

would the same size of an mdf board and the same size of a board of pine used for shelving have the same weight bearing strength, both being 3/4 inch thick x 72 x 17? thank you

By anon40281 — On Aug 07, 2009

I suspect any recycled material in MDF would largely be accidental. Wikipedia says they chip whole debarked logs. I can't imagine a mill producing 100s of tons of composite products like MDF fooling around with sticks and twigs. They don't want bark and they don't want nails.

By anon37305 — On Jul 18, 2009

how can you put a slight compound curve in a 30"x36" sheet of MDF board?

By keyboardsart — On Jun 06, 2009

Currently am working now with a marble flooring on top of MDF wood substrate. Do you think MDF wood substrate will not swell after it totally got wet from the volume of water we mixed with the tile glue? *Is it water resistant?*

By handyman — On Mar 13, 2009

Of course it is toxic tool, it has formaldehyde resin in it which is in the dust. So no, you shouldn't breathe it in.

By alvinsanity — On Aug 23, 2008

im an industrial design student and i was wondering what kinds of furniture specifically that i can use MDF on?

By davianny — On Jun 14, 2008

Would MDF make for a suitable Table top for an outside picnic/Patio table. If not, then what would be suitable, a hardwood?.

By anon14318 — On Jun 14, 2008

Can mdf ever be used in an exterior situation? Like using as a platform or anchor winch mounting in a boat if it is covered with marine carpeting?

By zena — On Jun 05, 2008

hello all, i am working in a factory which generates a significant amount of MDF dust (milldust),which sent to landfills. my question is : if there is a specific material (like a: resin, glue...) which mixed together with the mdf dust, and thus making a mixture for pouring in a mold ? Where i can get like this material ? thank you all

By joshklipsch — On Apr 15, 2008

Hello all. I had a question about MDF. I'm working for a company trying to get to the bottom of some bowing issues in furniture that's made of MDF. We're seeing it happen on a lot of tops and shelves where the large flat MDF surface is starting to droop and/or bow. It looks like this is a normal issue with MDF, but my question is whether or not there are common ways to fix this or improve it?

By anon9108 — On Feb 28, 2008

First, never trust rubberband masks. Aren't your lungs are worth more than that? 27 USD will get you something you can fit to your face and you will definitely feel the difference. Enough to know you're doing yourself a favor.

as to the worth of MDF, to me, it's like that old (blues) saying about the older woman, Old women don't tell, they don't' swell, and they're grateful as h*ll."

MDF covers nicely, edges too!, it don't swell, or move or split (the metaphor may break a bit here ;)) and it will thank you by lookin' good for less $$$

And I have made a LOT of mdf dust.

As far as the formaldehyde, I used some of this around say, 1980's. I remember when it got hot, LOTS of the formaldehyde smell. Last year, and very soon this year, I am going to/have cut up several 49x97's into many many chunks and glue it up with TitebondII into many cool useful things. I don't get anywhere near the smell these days.

Just my $0.02+ =8^>

By anon8850 — On Feb 22, 2008

very useful information

By anon7124 — On Jan 18, 2008

MDF contains formaldehyde so yes it can be toxic and yes it can give off gas. I've heard that the amount of gas given off is actually large, not small as one poster on this discussion said. Also, there are more cons to MDF. It can snap like dry twigs, which properly cured wood never does. It is also not true that it is more environmentally safe. Yes it uses scrap lumber, but it binds it with resin, which has formaldehyde in it. Give me wood any day.

By anon4305 — On Oct 12, 2007

To try and answer the third question: MDF is made by attrition milling wood scraps, then applying a resin to the fibers, then consolidating the fibers with heat and pressure into a panel product. There are two main resins that are used to adhere the particles: urea formaldehyde and phenol formaldehyde. There is a limit placed on the formaldehyde emission of the MDF by ANSI (American National Standards Institute) of .3 parts per million. The MDF that you purchase should have a tag or stamp on it somewhere that says that it conforms to ANSI A208.2-1994. The amount of formaldehyde in typical MDF is not significant enough to be toxic. To put it in perspective, OSHA allows an exposure of .75 ppm during an 8-hour work day.

That being said, if you are cutting MDF, you should always take safety precautions: one of those dentist masks should be fine for your mouth and nose, and safety glasses and gloves. Hope this answered your question.

By anon4237 — On Oct 08, 2007

Does anyone know if I should be concerned about off-gassing from a desk which is made from MDF and coated with a few layers of varnish? Please advise.

By anon3810 — On Sep 18, 2007

Is there a difference between MDF and standard untempered hardboard (masonite)?

By anon1601 — On Jun 07, 2007

Is exposed or particles of MDF released into the air toxic? And how much do they give off gas?

By anon743 — On May 03, 2007

I just used mdf as wainscoting in the dining room. I primed it with oil based primer and used a semi-gloss paint, but now it looks bumpy like an orange peel. What can we do?

By anon443 — On Apr 25, 2007

Does MDF used as interior moulding need to be primed before painting?

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