Is your Memory Foam Mattress Topper Not Expanding? Here are Tips to Fix It

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Memory Foam mattress toppers are important for people who seek comfort and body support as they sleep. They sit on top of a regular mattress, whether old or new, and adjust its level of firmness and comfort. They conform to the body shape and ensure an even weight distribution while relieving pressure points and keeping a neutral spine alignment. Some models are even available with extra features for motion isolation and temperature regulation. This article will cover helpful tips if a memory foam mattress topper is not expanding.

Memory foam mattress toppers can take up to 72 hours to expand. To make a memory foam mattress topper expand faster, place the mattress topper on a flat surface, warm the room, loosen the foam layers of the topper, and finally ventilate the room.

There can be various reasons for improper expansion of a memory foam mattress topper, including the room being too cold, or the topper being compressed for a long time, the topper could be too thick and dense, or the topper might just be faulty. Read our article on gel vs. memory foam mattress toppers to find out more about these popular topper materials.

Here are the steps to take to fix a memory foam mattress topper expansion that's not expanding. These are particularly important when you first unroll a mattress topper and after rolling up a mattress topper and keeping it in storage.

Related articles:

• We've discussed tips to choose a mattress topper, especially for a heavier person, in our article

Step 1. Place the Memory Foam Mattress Topper On a Flat Surface Like the Floor or a Bunkie Board

A flat surface promotes an even expansion of the topper. Avoid placing the memory foam mattress topper directly on the bed frame immediately after unpacking it, as this may cause uneven expansion, especially at the corners. Place the topper on the floor and give it some time to naturally expand. We like this bunkie board from Amazon because it is easy to install. But once it's expanded, always make sure to use your mattress topper properly. Read our article about using a mattress topper on a box spring instead of a mattress for more information.

Step 2. Warm Up the Room To At Least 20 C

Foam responds to temperature - it tends to be firmer in cool temperature and softer in warm temperatures. So set the room temperature to at least 20°C (68 °F), as warmth encourages expansion. This temperature and humidity monitor from Amazon will come in handy for determining the room temperature because it has an app alert.

Step 3. Loosen Up the Foam Layers by Walking On Top of the Mattress

Loosen up the foam layers of the mattress topper by rolling on top of it or by simply walking around the edges for a few minutes. This may sound unusual, but body heat and constant movement activate the foam and help loosen the material.

Step 4. Provide Ventilation By Opening Up the Windows In the Room

Providing ventilation can help the mattress topper expand fully. Improve the air circulation by opening the windows or turning on a fan next to the topper. Improving ventilation may not only help the topper with expansion, but also with off-gassing. To learn more about the process of off-gassing read this article by Essentia titled 'Are There Chemicals in Mattresses?'

Step 5. Replace Your Memory Foam Mattress Topper If It Doesn't Expand Fully After A Week

Keep in mind that in some cases, the mattress topper fails to expand even after significant time has passed and all the tips to help it expand have been tried. Chances are the mattress topper is defective and the best solution would be to return it, and replace it with a higher quality mattress topper. We recommend this Puffy topper from Puffy because it has a 101 day sleep trial and its one of our favorite (after testing 20 brands).

How Long Does It Take A Memory Foam Mattress Topper to Expand

Unrolling a memory foam mattress topper on top of a mattress after full expansion. Image from Amazon.

A memory foam mattress topper takes 24–72 hours to expand fully. It expands up to 90% in about 4-6 hours, and requires a few more hours to completely expand. Therefore, it is advised to wait 24 hours before sleeping on a memory foam mattress topper.

Is your memory foam mattress not expanding? The expansion time of a memory foam mattress topper depends on factors such as the room temperature and the topper's density and thickness. Generally, the thinner and less dense a memory foam mattress topper is, the faster it will take to fully expand, especially in a warmer room. This high-quality mattress topper from Puffy is made with a low-density and breathable open cell memory foam, which helps soften the mattress.

The expansion time is also influenced by the amount of time the topper stays wrapped and rolled inside the shipping box. Therefore, it is recommended to unroll it as soon as the package arrives. To learn how to properly install a mattress topper read our helpful article.

Can You Sleep on a Mattress Topper the First Day?

Deciding to sleep on a mattress topper the first day won't damage the material in any way. On the contrary, the bodyweight and body heat will help decrease the material's expansion time. Just wait for about 4-6 hours before using the mattress topper to allow off-gassing.

It is safe to sleep on a memory foam mattress topper on the first day if the mattress topper has been allowed to expand and settle for at least 4-6 hours. The recommended expansion time for a memory foam mattress topper is 24-72 hours, so the topper might feel different after the first night.

Reasons Why The Memory Foam Mattress Topper Is Not Expanding

There are various reasons why a mattress topper may not expand, which include the topper being compressed in a box for too long, the topper being too thick or too dense, the room temperature being too cold, or the topper being defective.

Reason 1. The Mattress Topper is Compressed In a Box For Too Long

Mattress toppers are deflated, folded and packed in a box. If the mattress topper stays too long in the box it takes more time to expand. So when receiving the package it's better to unpack it immediately.

Reason 2. The Mattress Topper Is Thick and Dense

The expansion time of memory foam mattress toppers depends on how thick and dense the mattress topper is. Generally, the denser the topper is, the more firm it is, and the longer it takes to fully expand. Read our article titled, "What's the mattress topper hack?" to learn more about choosing a mattress topper.

Reason 3.The Room Is Too Cold

Memory foam mattress toppers are temperature-sensitive. They feel firmer at cooler temperatures. They will start expanding as soon as the memory foam warms up. Heat improves the viscosity of the foam and increases its pliability, making it easier to mould. We like this medium firm mattress topper from Amazon because of its durability and flexibility at room temperature.

Reason 4. The Mattress Topper Is Defective

If the mattress topper fails to expand even after a week or so, then chances are that it is faulty. Consider returning it in this case. We recommend this 5 stars mattress topper from Puffy because it offers a lifetime warranty and an amazing comfort.

What Happens if You Sleep on a Memory Foam Mattress Topper Too Soon?

Sleeping on a freshly unpackaged mattress may be unpleasant due to slight off-gas odors.

Let the mattress topper air out for a few hours to allow off-gassing and then sleeping on top of it will improve within 24–72 hours.

Sleeping on a memory foam mattress topper too soon will result in the product not feeling its best, but it will speed up the expansion process. Sleeping in the bed, turning around, body heat, and body weight will help loosen up the foam.

For more information about how to speed up the expansion time, read our article on how long it takes a memory foam mattress to expand.

How Do You Properly Roll a Memory Foam Mattress Topper for Storage?

This vacuum compression bag is used to compress a mattress topper in order to move it easily and store it away. Image from Amazon.

Mattress toppers are as important as mattresses. They increase the longevity of the mattress and provide a higher level of support. Because of this, they should be maintained and stored properly. You can find more information in our article on how to store a latex mattress topper as well.

To properly roll a memory foam mattress topper for storage, first thoroughly clean the topper, then roll it up and put it in a storage bag, and finally store it in a dry and cool environment.

Step 1. Clean the Memory Foam Mattress Topper

Before storing away a mattress topper, clean it and treat its stains and unpleasant smells, otherwise dirt, dust, mold and bacteria will accumulate. Vacuum the mattress topper, spot clean the stains, and use a mild cleaning mixture to ensure the topper is clean. Air the mattress topper out before storage to avoid the breeding of mildew. For more information on how to properly care for a mattress topper, visit our article where we discuss how to clean a mattress topper.

Step 2. Roll Up the Mattress Topper

Roll up the memory foam mattress topper to save storage space and to move and relocate the product more easily. Avoid folding a topper, as this causes creases and folds, and damages the material. Creases are especially detrimental for mattress toppers on hospital beds because they create pressure hotspots.

Step 3. Put the Mattress Topper In a Storage Bag

Use storage bags to protect the mattress topper from dust and dirt, which can damage the product. Use the original packaging, or purchase a plastic bag or a mattress vacuum storage bag to save space and keep dirt out. This mattress vacuum storage bag from Amazon can safely store a 6-inch foam mattress when needed.

Step 4. Store the Mattress Topper In a Dry and Cool Space

Store the mattress topper in a dry and cool place environment, where dirt, mold, and mildew are less likely to accumulate. Choose a place inside the house with low humidity or opt for a climate-controlled storage unit.

In a Nutshell

Memory foam mattress toppers take about 24–72 hours to fully expand, but this time can be decreased by placing the topper on a flat surface, warming up the room, flattening and pressing the topper along the edges and corners as it unrolls, and increasing the ventilation in the room. To find out more about the benefit of mattress toppers read our complete guide. Also, if you find that you're uncomfortably warm sleeping on your mattress topper, take a look at how to fix a mattress topper that's too warm as well.

Mattress Topper Not Expanding: Complete Topper Guide

A quality mattress topper can transform an uncomfortable mattress at 10–20% the cost of replacement.

Topper Selection Guide

When a Topper Is Not Enough

If your mattress has visible sagging deeper than 1.5 inches, a topper will conform to the sag rather than correct it. At that point, mattress replacement is the better investment.

Related: pad vs protector | topper lifespan.

The Saatva Classic includes built-in premium comfort layers - no topper needed. 365-night trial.

All scores in this guide come from our MattressNut Sleep Lab methodology, applied identically across every mattress we evaluate.