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When you buy a mattress-in-a-box, you’ll need to let it expand before using it. This usually only takes a few hours, but there are rare cases when your new memory foam mattress corners don’t expand properly. In this article, we’ll diagnose the problem and give you the solutions.
Why your new memory foam mattress isn’t expanding
When you remove your new mattress from the box, it should begin expanding immediately. If it isn’t expanding properly, there are a few possible causes:
- You haven’t given it enough time – Memory foam mattresses begin expanding immediately, but it can take up to 72 hours for them to fully expand, especially at the corners. Give it more time.
- Your room temperature isn’t warm enough – Warmth encourages expansion. If your room temperature is too cool, then the expansion process is going to be much slower. If it’s extremely cold in your room, it may not expand at all.
- You didn’t remove it from the box quick enough – Most bed-in-a-box brands recommend removing a memory foam mattress from its packaging within a few days of receiving it. If it stays compressed for too long, then the memory foam may not expand properly.
- You bought a defective mattress – In the worst case scenario, it’s possible that you bought a mattress that wasn’t constructed properly and needs to be replaced or disposed of.
What to do if your memory foam mattress is not expanding
Here are the steps you should follow if you want your new memory foam mattress to expand fully.
Increase the room temperature
Memory foam is temperature-sensitive. We recommend using a space heater or fan heaters to provide warm temperatures in your bedroom, which will help most new mattresses completely expand. We recommend a room temperature of at least 68 degrees Fahrenheit to help your mattress expand faster. Cooler temperatures can cause expansion issues. Your body heat during the first night of sleep on your new mattress will also aid the expansion process.
Put it on a flat surface (such as the floor)
If you think that your box spring or bed frame isn’t providing a flat, stable surface for your memory foam mattress, then we recommend letting it expand on the floor for at least 24 hours. Once it’s fully expanded, you can place it back on your bed frame. A platform bed can also provide a stable surface for your mattress to expand.
Improve air circulation
Most mattresses will expand faster if you open a window to create a draft or use a fan to improve the air circulation in your bedroom. Denser foam needs greater air circulation to expand fully. This also has a side benefit of reducing off-gassing.
Massage the mattress
We recommend walking or rolling around on your new mattress to get full expansion from the foam layers. This is particularly important if the mattress you bought is made out of denser foam.
Return the mattress for a replacement
If your memory foam mattress still isn’t expanding after following all of the above steps, it’s likely defective. Fortunately, most of the best mattress brands offer a free sleep trial period that gives you the ability to return or replace it free of charge. Most sleep trial periods range from 100-365 nights (some even have longer trial periods).
All you have to do is contact the manufacturer and let them know that your new memory foam mattress isn’t expanding. We recommend giving it 72 hours to expand before contacting the company.
Frequently asked questions
How long does it take a memory foam mattress to expand?
A bed-in-a-box can take up to 72 hours to expand fully.
Most brands claim that their memory foam mattresses expand much faster – usually less than 24 hours. Some companies even state that you can expect the expansion time to last only a few hours.
If you’ve waited the full 72 hours and your new bed still hasn’t expanded, then we recommend that you troubleshoot by following the steps we listed above. If that doesn’t work, then you should contact customer service and let them know that you have a defective mattress. All reputable manufacturers have policies ensuring customer satisfaction and most have a sleep trial period. If your memory foam mattress isn’t expanding, they will replace your old mattress with a new one.
Why are the corners of my memory foam mattress not expanding?
Memory foam mattress corners are usually the last part of the bed to fully expand.
If you just bought a new bed-in-a-box and the corners aren’t expanding, the first thing you should do is to give it more time. The memory foam in the middle of the bed will expand first before moving outward towards the edges and corners.
If you’ve given it 72 hours and the memory foam mattress corners are still not expanding, make sure you follow the steps we listed above. Uneven expansion can be annoying; but increasing the temperature (e.g. by adding body heat), increasing air circulation, and placing the mattress on a flat surface can reduce expansion times considerably.
Which memory foam mattress brands have expansion issues?
Most premium bed-in-a-box brands such as Saatva and Dreamcloud will expand without issue.
The brands that have the most problems with improper expansion are usually the really cheap ones that you can buy on Amazon or similar sites. Most people won’t have any issues with buying a cheap memory foam bed, but there is a slight chance that you’ll encounter problems.
Based on consumer reports, some people experience problems with the following memory foam mattress brands:
- Zinus
- Lucid
- Wayfair
- Blackstone
- Mainstays
- AmazonBasics
Conclusion
Most memory foam mattresses will expand within 24 hours without any issues. In rare cases, it can take up to 72 hours for your mattress to completely expand.
There are a few steps you can follow to make your mattress expand faster. To make a memory foam mattress expand; you need to improve airflow, increase the temperature, massage the mattress to help loosen memory foam, and place it on the floor for 24 hours. Many customers have used these strategies to fully expand memory foam mattresses.
If your new memory foam bed still isn’t expanding, then we recommend taking advantage of the trial period that most companies offer. Reputable brands all have manufacturer guarantees that protect you in the event of receiving a defective product. Worst case scenario is you’ll have to return your old mattress and get a new one.
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He's been involved in the mattress industry for almost a decade and is dedicated to using his expertise to help you choose the right mattress.
Robert's main goal is to give you straightforward info on what works - and what doesn't - so you can spend less time stressing about sleep and more time living your life (that's what we're all here for, right?).
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