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Does MDF Expand and Contract? (All You Need to Know)

Are you planning to use MDF for your woodworking project? However, are you wondering whether or not MDF can expand and contract?

Are you also wondering whether moisture and temperature changes can cause MDF to expand and contract with time and usage?

Does MDF expand and contract?

MDF can definitely expand and contract. Accordingly, this is because MDF is not really natural wood rather it is compressed wood made out of wood particles and resin. Therefore, MDF is highly sensitive to humidity and moisture which can cause MDF to expand and contract.

MDF woods have diverse usage when it comes to woodworking therefore being knowledgeable about whether or not MDF trim and MDF boards are susceptible to expanding and contracting will help you to mold your decisions accordingly.

MDF trim: 

MDF trim can definitely be prone to expanding and contracting With usage. 

Accordingly, this is because if you expose MDF trim to humid temperature then the resin or glue that combines the wood particle in MDF wood will be loosened which will thus cause the MDF trim to expand and contract in the process.

MDF board: 

MDF board is the most prone to contracting and expanding because when this board comes in contact with moisture, it can swell which will lead to expansion.

In addition, when it comes to dry and warm temperatures, the MDF board can contract very easily and all these negative effects will eventually warp, crack, and bend your MDF board.

Does MDF expand and contract like wood? 

It is really important to know whether or not MDF expands or contracts like wood so that you can avoid confusion and mold your decisions accordingly to surpass any unwanted situations.

When wet: 

One of the most unwanted disadvantages of using MDF wood is that it can expand when it comes in the contact with water and it is highly absorbent of water.

In addition, although MDF follows the same nature of expansion or contraction under moisture as solid wood, MDF nevertheless will be damaged by water more frequently.

This is because wood is a natural product without other elements polluting it but MDF is basically several wood particles joined or compressed together with the usage of glue or resin which is why MDF is more prone to expand or contract when it is wet.

In heat:

MDF can definitely expand and contract in heat. Accordingly, if the temperature is humid, then the moisture in the MDF will be increased which will lead to swelling or expansion of the MDF wood in heat.

In addition, if the temperature is warm or dry, then the heat will evaporate the moisture content within the MDF wood which will lead to the contracting of MDF wood.

How much does MDF expand and contract? 

Engineered wood like MDF can expand or contract to a certain degree especially when the moisture content or the humidity level of the environment fluctuates.

In addition, how much MDF will expand and contract will also depend on the density of the board, the thickness of the board, and the content of the adhesive used.

Therefore, depending on such factors, the exact percentage of expansion and contraction may vary but MDF can expand or contract by about 1 percent on average.

“3″ reasons why MDF expand and contract

Several reasons can contribute to making MDF expand or contrast therefore being knowledgeable about such reasons will help you to mold your decisions accordingly.

Moisture content:

One of the most common reasons that contribute to the reason why MDF expand or contract is related to the moisture content.

In addition, MDF is highly absorbent of moisture which is why when it absorbs high levels of moisture, it can expand as a result of it.

Temperature changes:

Temperature change is another thing that will affect MDF woods however MDF can deal comparatively well with temperature changes than solid wood.

Nevertheless, MDF woods or boards cannot withstand varying humid weather or dry weather.

Moreover, if the temperature is very humid, then the moisture in the MDF will be more prominent and this will lead to the expansion of the MDF. In addition, if the temperature is dry then MDF wood will contract.

Excessive weight:

Another reason why MDF seems to expand and contract is due to the fact MDF is made out of compressed wood particles that are joined together with wax or resin which makes MDF pretty heavy.

Accordingly, with time and usage, these MDF boards or woods will sag meaning MDF woods will contract and expand easily.

Does MDF shrink? 

Because MDF is a manufactured wood that is made out of a mixture of different wood particles and resin or wax, MDF is highly prone to timely decay and is very much exposed to shrinkage.

Moreover, whether or not MDF will shrink depends a lot on the environment around you as a humid environment tends to shrink MDF faster.

In addition, MDF is not really solid wood and therefore MDF will have a shrinkage of about .25 percent whereas natural solid wood will only have 0.05 percent of shrinkage.

Moreover, this is why while working with MDF, you have to take into account the percentage of shrinkage and you should be mindful of using this fact while installing MDF board to make cabinets, shelves, furniture, and so on.

Do you need to seal MDF to prevent expanding and contracting? 

It is not only MDF rather every other wood needs sealing to prevent expanding and contracting. 

Accordingly, if you do not seal MDF, then you risk MDF to a lot of damage regarding cracking, chipping, and so on.

In addition, sealing of MDF wood is basically like applying a layer of protection on MDF so that it doesn’t fully perish under high temperatures, humidity, heat, and so on.

Moreover, sealing your MDF wood will not only prevent expanding and contracting to some degree rather it will also give durability to your MDF wood.

However, as MDF is not really real wood rather it is made out of wood particles combined with resin and wax, you cannot expect MDF to work like wonder after it is sealed.

In addition, sealing your MDF Will nevertheless give your MDF wood or board a more lively look.

How do you stop MDF from expanding and contracting?

It is no news that MDF board or woods really are prone to expanding and contracting in certain environments therefore, being knowledgeable about the proper ways to stop MDF from expanding and contracting will help you to mold your decisions accordingly and avoid confusion.

Identify the damage:

It is no surprise that MDF boards or woods are very absorbent which means MDF can be prone to excessive expanding and contracting. 

Therefore, you have to identify the damage on the MDF wood or boards first to determine how damaging the situation is regarding expanding and contracting so that you can act accordingly and repair rightly.

Gather the equipment:

In this step, you now need to make sure you have all the things needed for stopping MDF wood’s expansion or contraction. Accordingly, you will need appropriate sealant, gloves, varnish, cloth, and so on.

Seal MDF: 

One of the best things you can do to prevent expanding and contracting of MDF wood or board is related to the usage of sealant which works as a protective layer on the MDF so that it doesn’t damage as much as before.

In addition, any kind of oil-based varnish, PVA-based glues, MDF primer, polyurethane, and so on can be used to work as a sealant for your MDF board so that it can become somewhat water-resistant as MDF boards aren’t really water-resistant.

In addition, you should first use a primer to prep the MDF board before putting sealant on it.

After the primer is all dried up, you now need to apply the sealant onto the MDF board and let it dry for a couple of hours.

Moreover, you can add several layers of sealant nevertheless you should make the final product dry fully for three to four days which will make your MDF wood or board work with full potential.

In addition, when it comes to sealant, you can use any kind of sealant be it varnish, stain, wood sealant, or moisture-resistant paint.

Moreover, another type of coating or sealant that you can use to protect your MDF from expanding or contracting is related to melamine which is basically a plastic laminate that you can put on the MDF.

Whatever the sealant may be, sealing your MDF wood will make MDF board or wood waterproof and will give your MDF woods a very classy look.

Final Thoughts

To sum up, although MDF wood or board is a great alternative to solid woods, MDF wood nevertheless will be prone to expanding and contracting over time as high moisture content, dry temperatures, humid temperatures, and so on will cause such severe situations.