Do Memory Foam Mattresses Sag?

When you buy a mattress, the last thing you want or expect is for it to start drooping or sinking in certain areas. Sagging mattresses not only look and feel bad, but they can also compromise your health over time.

So, do memory foam mattress sag? Memory foam mattresses are designed not to sag. Their internal structure self expands when the weight is taken off, allowing it to bounce back into shape. However, due to its spongy nature, memory foam can compress faster than other mattress types (especially cheaper ones), so you need to be aware of how to reduce the settlement or ‘sag’ amount to limit the dipping over time.

We provide some handy tips on how to avoid the problems associated with saggy memory foam beds and answer any burning questions you have on the topic. We'll be covering the below:

• Sagging mattresses explained
• Causes of a sagging mattress
• How to spot a sagging mattress
• How to prevent and fix a sagging mattress

Sagging Mattresses Explained

A saggy mattress is the loss of tension in the materials of the mattress which could reflect the mattress itself or a poor foundation and bed frame. The design of a memory foam mattress is to mould and adapt to the contours of your body, providing more support and pressure relief than a regular sprung mattress.

Memory foam is made up of the polymer polyurethane, which is combined with hard-working chemicals to give it its viscosity. This is what gives it that soft, sinking feeling when you get into bed. However, over long periods of compression, the memory foam can get squashed and held that way for a long time, hence the dipping. 

Causes of Sagging Mattresses

Your memory foam mattress could be sagging for the following reasons:

• Frequent use
• Sleeping positions
• Placing the mattress on an uneven surface
• The inner component disintegrating in older mattresses 
• High moisture content
• Inadequate care

How to Spot a Sagging Mattress

To check if your mattress has sagging areas, lay something flat across the top surface of your bed and look for gaps underneath. Common areas are usually where heavy spots of the body lay like the head, hips and shoulders. 

How to Prevent and Fix Sagging Mattresses

1. Memory Foam Mattress Topper

Finding it difficult to sleep on your existing mattress but not ready to replace it yet? The simplest and most effective way to solve a sagging memory foam mattress issue is with a mattress topper or mattress pad. While this might not be a permanent fix, it’s cheaper than buying a new mattress and can improve the quality of your sleep by adding an extra comfort layer. A thick topper can also help to fill in slight indents in your mattress. 

Worried about compromising the feel of your mattress? We can reassure you, adding a supportive layer to the top of the mattress doesn’t take anything away from the mattress itself. 

2. Add More Mattress Support

If you have a saggy memory foam mattress, the problem could be your mattress foundation or bed frame. Memory foam is a heavy mattress material and therefore needs more support. Without sufficient support, you’ll start to see saggy areas - slats with gaps measuring 3 inches or wider can cause the mattress to sag in spaces. It’s best to look at secure and solid bed frames which will provide more support to the mattress.

3. Rotate the Mattress

A simple, yet effective solution is to rotate or flip the mattress. When you turn your mattress it will prevent continuous pressure in the same place and help prevent sagging and can even out the foam be redistributing the weight. If you’ve rotated the mattress and it’s still sinking, try flipping it. It’s recommended to rotate your mattress every 6 months. 

Frequently Asked Questions

How many years should a memory foam mattress last?

An average memory foam mattress should support and comfort you for around 8 years. More expensive, higher density foams can last even longer and cheaper items will likely wear out faster and could start to sag in a matter of months.

What thickness is best for a memory foam mattress?

Our memory foam mattresses come in different thickness layers of 3cm up to 10cm. The thickness varies from person to person and depends on your weight, sleeping style and health and mobility. The thicker, the better in terms of wear and tear. While the cost of the mattress will increase as you go up in size, so will your protection from sag. Thinner memory foam will sag faster because you’re putting more pressure on the mattress and base below.

To help you choose, check out our thickness guide for more information.  

How much should my memory foam mattress sag?

The industry-accepted ‘sag’ level or amount of settlement is 2-3 centimetres or around 1.5 inches thick, meaning any indents of 2cm-3cm that don’t return to their original position are considered acceptable.

Can a sagging mattress affect my health?

A sagging mattress can cause spinal pain or stiffness because it throws your spine out of proper alignment. The sagging comfort foams can also restrict the passage of air through the coil layers, resulting in a hotter and more uncomfortable night’s sleep. And it’s important to remember, not getting good quality sleep can also be detrimental to your health.

Which type of mattress will sag more: memory foam or a pocket sprung mattress?

It is thought that a memory foam mattress will sag more easily due to its moulding nature, compared to traditional sprung or box spring mattresses. This isn’t necessarily true; whilst traditional mattresses don't look as if they sag on the surface, their uneven feel and lack of support in certain areas can speak volumes.

Why not combine high-density foam and pocket springs for extra support and maximum comfort? A hybrid mattress is the ultimate sleeping experience and they’re one of the most popular ways to good night’s sleep! 

Finding the Perfect Memory Foam Mattress

Our high-quality memory foam mattresses are designed to relieve pressure on the body by distributing your weight evenly, providing ultimate support whilst you dream. We know the importance of getting your mattress choice absolutely right, so in case of any uninvited sagging in the first few months, we offer a 100-night trial on all of our mattresses.