How to fix a sagging mattress: Tips & tricks

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A mattress that is lumpy, out of shape or showing visible permanent sagging will not improve over time and will need to be replaced. But in the meantime, turning your mattress or replacing your bed base may help.

Over time, mattresses can sag and become uncomfortable. Sagging usually occurs in the middle of the mattress. When this happens, you will notice it immediately when you lie down. Your mattress may feel unsupportive, and you might even feel the base underneath, a sensation known as ‘bottoming-out’.

A sagging mattress will put the spine out of alignment, causing pain, discomfort, or difficulty turning over in bed. 

Although a sagging mattress will eventually need replacing, there are steps you can take to make it more comfortable in the meantime.

mattress sagging in the middle
A sprung mattress that has sagged and collapsed in the middle.

What causes a mattress to sag?

All mattresses will eventually sag as the components inside the mattress break down and lose their ability to recover. Sagging can result from normal wear and tear, poor-quality materials, faulty craftsmanship, inadequate support or neglect.

Wear and tear

Normal wear and tear is a common cause of mattress sagging. The mattress’s components naturally flatten with regular use. Dips and indentations may become more noticeable across the sleeping surface, especially in areas where most of the sleeper’s weight is concentrated, like the shoulders and hips.

Single-sided mattresses tend to wear out sooner because weight and pressure are concentrated on the same areas. In contrast, double-sided mattresses typically last longer as they can be flipped to distribute wear across both sides evenly.

Mattress quality

The quality of materials inside the mattress can also affect sagging. Higher-quality natural materials, such as wool, latex, and horsehair, are resilient and retain their shape well over time. Latex, in particular, is exceptionally durable and often outperforms other materials.

In contrast, lower-quality synthetic materials, such as polyester or polyurethane foam, tend to break down much sooner, making sagging more likely.

Mattresses are constructed with different layers for comfort and support. The base layer, located underneath the comfort layers, must be made of sturdy materials to provide support and resist sagging. It is typically constructed with foam or springs.

In foam mattresses, the base layer can vary in quality. Cheaper models often use low-grade foam, which can crack or break down quickly. In contrast, higher-quality foam mattresses use high-density foams or latex, which are more durable and resistant to sagging.

In sprung mattresses, the base layer is typically made from coil springs or pocket springs. Coil springs are commonly used in low to mid-end mattresses as they can be mass-produced cost-effectively. Coil springs are arranged in rows and connected with thinner helical wires to form the spring unit. One of the main drawbacks of coil springs is that since they are interconnected, if a spring breaks, the surrounding springs may sag or collapse, affecting support.

In contrast, pocket springs are individual springs that work independently. They provide better-targeted support; if one spring breaks, the others are unaffected.

Choosing a mattress with proper edge support ensures the perimeter remains sturdy and supportive. This extends the usable sleeping area and reduces the likelihood of premature sagging. Cheaper mattresses typically have weak edges that may collapse or sag under pressure. Pillow-top mattresses, which have an additional comfort layer sewn or stitched into the top of the mattress, may be more prone to sagging if poorly constructed.

In contrast, high-quality sprung mattresses are hand-side stitched. This labour-intensive technique involves stitching the side panels to the outer rows of springs. Hand-side stitching reinforces the perimeter, providing more support and stability.

Usage

How a mattress is used affects whether a mattress sags. Sleeping in the same area of a mattress each night causes uneven wear, which can eventually lead to sagging.

Body weight also affects sagging. Heavier individuals put more pressure on the mattress, which can gradually lead to sagging. This is particularly noticeable when couples with significantly different weights share a mattress, as sagging is often more prominent on the side of the heavier person.

Regularly sitting on the edge of the bed can cause the mattress to sag prematurely around the perimeter. Sleeping near the edge can make you feel like you are falling or rolling out of bed.

Neglect

Neglect and improper use can significantly contribute to mattress sagging. For example, most mattresses require regular turning at least once a month. Failure to do so causes uneven wear, as pressure and weight are concentrated in the same areas of the mattress, which can eventually lead to sagging.

Most manufacturers recommend using a mattress cover to protect the sleeping surface from stains and spillages. Without protection, liquids can penetrate the mattress, damaging its components and causing premature sagging. An unprotected mattress also provides the perfect conditions for mould and bacteria.

Inadequate support

Placing your mattress on an unsuitable bed base can also cause it to sag. The bed base provides the underlying mattress support. If it is uneven, the mattress will conform to its shape, dipping in the same areas.

Similarly, slatted bed bases with slats that are too far apart can cause the mattress to sag between the gaps.

How to fix a sagging mattress

You can’t properly fix a sagging mattress unless you replace its components. However, some checks and fixes can make your mattress more comfortable and manageable until you replace it.

Turn your mattress

Regularly turning your mattress, especially during the first few weeks of use, helps the fillings settle more evenly and reduces sagging. Non-turn mattresses cannot be flipped but can occasionally be rotated end to end. Double-sided mattresses can be flipped and rotated to ensure even wear on both sides.

Always refer to the manufacturer’s care instructions to ensure you turn your mattress correctly.

Replace your bed base

If your mattress is in good condition, it could be the bed base causing it to sag. An old, worn-out bed base will not provide adequate support, and if it sags or has collapsed, the mattress will conform to its shape.

Carefully remove the mattress to inspect the condition of your bed base. Check for visible signs of wear or damage, such as dips, indentations, or loose components. Run your hand gently along the surface to feel for any protruding springs or squeaky, unstable components that could affect support.

For slatted beds, sagging can occur if the slats are too far apart. Refer to the manufacturer’s recommendations for slat spacing. If necessary, reinforce the bed by adding extra slats or placing a sheet of plywood board over the slats to create a more even surface.

When replacing your bed base, ensure the new one is compatible with your mattress. Some mattresses perform better on slats or solid bed bases. Also, ensure the bed base is strong and sturdy enough to support the mattress’s weight.

Use a mattress topper

A mattress topper is an additional layer of bedding that you place on your mattress to make your bed more comfortable. Mattress toppers are available in various materials, such as polyester, memory foam and latex. They tend to be around one to four inches deep.

A deeper mattress topper provides more cushioning and may alleviate the effects of sagging by providing a more consistent sleeping surface. However, a thinner mattress topper may be less effective, as it will simply conform to the mattress dipping in the same areas.  

Use extra pillows to fill sagging areas

You could temporarily place pillows, cushions, or rolled towels in areas where the mattress is sagging. However, these items may not provide adequate support and could shift as you move in bed, potentially disturbing your sleep.

Can you complain about a sagging mattress?

Mattress sagging is a common customer complaint. It is generally caused by normal wear and tear and is not usually covered by a manufacturer’s guarantee or warranty.

If your mattress is relatively new and shows signs of premature or excessive sagging, it could be due to faulty materials or poor craftsmanship. There is no industry standard for excessive sagging because too many variables, such as the materials, weight distribution and mattress age, affect it.

However, if you have followed the manufacturer’s care instructions, you may be entitled to a replacement or refund. Contact the seller if your mattress sags during its guarantee or warranty period. Local stores may arrange for a technician to inspect the mattress at your home to establish whether it is faulty. Online retailers may request photos of the sagging to assess the issue.

Can a new mattress sag?

After using your new mattress for a few nights, you may notice indentations and body impressions forming, particularly in areas where most of your body weight is concentrated. While a new mattress can sag, the dips and indentations that form are usually due to mattress settlement. This natural process occurs as the fillings inside the mattress gradually compress and adjust to your body’s shape.

Mattress settlement is perfectly normal and not a cause for concern. Turning your mattress regularly, especially during the first few weeks of use, will help the fillings settle more evenly.

Final thoughts

The typical lifespan of a mattress is between 7 and 10 years. If your mattress is sagging, uncomfortable, and affecting your sleep, replace it as soon as possible. 

Picture of About the author

About the author

Tony Brown is the founder and creator of The Bed Consultant. His career in the bed industry began in 2002. After graduating from university with a degree in Business Administration, Tony joined one of the largest independent furniture retailers in the UK as a bed consultant. Tony has helped thousands of customers find the perfect mattress.

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