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Memory Foam Mattress Corners Not Expanding – 5 Reasons Why

Don’t you just love the look of a memory foam mattress expanding? It’s a fascinating sight to say the least. But that’s not the only reason why it needs to expand. You see, these mattresses are designed to offer unmatchable comfort and ultimately a good night’s sleep. Expansion is a crucial part of the design.

With that, you certainly have a problem on your hands if your memory foam mattress corners are not expanding.

However, you do not need to worry about it because here, we are going to explain why that is happening and what you can do about it.

Why is it Necessary for Memory Foam Mattresses to Expand?

You see, memory foam is made from a unique material that reacts to heat and pressure. As such, when the mattress is first unpacked, it’s compressed and tightly rolled up to make it easier to ship and handle. That said, once you unroll it and remove the packaging, the mattress needs to expand to its full size and shape.

The heat and pressure of your body weight play an important role in mattress expansion because they activate the memory foam cells. Now, as these cells expand, they mold according to your body’s form and this provides customized support for your shape as well as sleeping position. Simply put, each time you lay down on your mattress, it will perfectly contour your body to reduce pressure points and offer maximum support.

You’d think that’s all, but it’s not. Your memory foam mattress needs to expand also because it needs to release air and any odors it may have picked up during storage and shipping.  

Reasons why a Memory Foam Mattress may fail to Expand

While it is rare for foam mattresses to fail to expand, it does happen. Here are some reasons why that may be.

Temperature: As we have previously mentioned, memory foam is temperature-sensitive, and if the room or environment is too cold, it could slow down the expansion. In such cases, the mattress may take longer to expand, or it may not expand fully.

Compression: Sometimes, these mattresses stay long in storage under too much pressure. If this is the case with your mattress, chances are that it may fail to expand as expected.

Quality: The quality of the memory foam used in different mattresses is not the same and this can affect expansion. If your mattress contains low-quality memory foam, it may fail to expand as expected or take longer.

Age: If your mattress has seen better days or has been in storage for a long time, it may not expand as expected. This is because foam can degrade over time, losing its ability to expand and provide support.

Moisture: Memory foam should not be exposed to humidity or moisture. If yours has, chances are that it will not expand properly.

Ways to Make a Memory Foam Mattress Expand

If you’ve recently purchased a memory foam mattress and it’s not expanding to its full size and shape, don’t worry! There are several steps you can take to fast-track mattress expansion:

Be patient: Yes, we understand you are excited to try out your new mattress, but you need to wait it out. Memory foam mattresses typically take between 1 to 3 days to completely expand. As such, the first and most important thing you can do is to give it time. Sometimes, that’s all it needs.

Increase the temperature: As mentioned earlier, memory foam is temperature-sensitive. So, if the room or environment is too cold, it can slow down the rate at which the mattress expands. To remedy the situation, you can try increasing the room temperature to speed up the process. However, make sure not to exceed the maximum temperature recommended by the manufacturer.

Massage the mattress: You’d be surprised what a simple massage can do for your mattress. By so doing, you help distribute the foam evenly and facilitate expansion.

Step on the mattress: This might sound outlandish, but walking on the mattress can help to distribute the foam and encourage it to expand fully. Just put on your socks and walk away. However, you need to do it evenly and gently, otherwise, you risk damaging the mattress.

Unwrap and remove the cover: Sometimes, the cover or wrapping around the mattress can limit expansion. If this is the case, try unwrapping and removing the cover, and then leave it to sit without restrictions so it can expand fully.

If you’ve tried these methods and your memory foam mattress is still not expanding as expected, contact the manufacturer or seller for further guidance.


What should I do if my memory foam mattress fails to expand after 72 hours?

The maximum amount of time you should give your mattress to expand is 72 hours. If after that time it has still not expanded, you may want to contact the seller or manufacturer for the next course of action.

Is it okay to sleep on my memory foam mattress before it fully expands?

No. This is not advisable because doing that may affect the integrity of the foam and consequently its ability to provide support and comfort.

Is it normal for a memory foam mattress to have an odor when first unpacked?

Yes, sometimes it happens. This is caused by the materials used in production. However, the smell should dissipate within the next few days after purchase.

Can I speed up the expansion rate of my memory foam mattress?

Yes, you can. For instance, you could try massaging the mattress, increasing the temperature in your room, walking all over it, or removing the cover to allow for full expansion.

Why did my memory foam mattress not expand fully?

It could be one or more of several reasons. Things like compression during storage and shipping, low temperatures in your room, storage time, and exposure to humidity or moisture may act as hindrances to your mattress expansion.

If you have done everything right and your mattress still doesn’t expand, you may want to contact the manufacturer for further guidance.