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How to Fix a Sagging Mattress

Written by Tuck Staff

Quick Overview

All mattresses eventually start sagging, and this can significantly affect how the bed feels – and how well its owners sleep. Mattress warranties protect against excessive sagging, but for many even minimal sagging can compromise mattress comfort and support. Thankfully, mattress owners can employ a few strategies to counteract the effects of sagging.

This guide discusses why mattresses sag and which mattress types are most susceptible to early sagging. We’ll also share a few tips for improving the feel of a sagging bed, and talk about the role mattress warranties play in sagging.

Why Do Mattresses Sag?

All mattress owners should expect some sagging from their bed. Mattress foams, latex, and other cushioning materials begin to become softer with prolonged use. Beds with springs also sag as coil tension decreases and comfort materials begin to sink into the support layers. This results in an uneven surface characterized by ‘peaks and valleys’ that can make the bed feel very uncomfortable.

Sagging most commonly occurs in areas that cushion the sleeper’s heaviest areas, such as the chest/shoulders, midsection, and hips. As the comfort materials deteriorate, prominent dips take shape in these areas. Side sleepers may actually benefit from some sagging; their position requires extra cushioning at the shoulders and hips in order to align the spine and alleviate pressure points. However, too much sagging can have the opposite effect, and even minor sagging can negatively affect spinal alignment for back and stomach sleepers.

Couples can also cause sagging, particularly if they spoon or cuddle in the center of the mattress while they sleep. This often leads to a deep, trench-like surface that may prevent them from comfortably moving toward the perimeter of the bed.

Sagging and Mattress Construction

It’s important to note that mattress construction often plays a role in sagging too. Poorly made beds with low-density foams and/or high-gauge coils usually deteriorate at a much faster rate than beds with more resilient materials. Price-points often reflect material quality, but not always. Customers can evaluate how much or little a mattress is likely to sag based on how dense the foams are (medium- or high-density are most durable) and how thick the coils are (low-gauge steel springs are the thickest and most resilient).

Shoppers can predict sagging to a degree by evaluating the mattress type, as well. Most mattresses sold today fall into one of five categories. The table below illustrates sagging potential for these five bed types.

How Does Sagging Affect Sleep?

Minor sagging may only impact sleep quality and duration to a minimal extent, if at all. However, significant sagging can have the following negative effects:

  • More pain and pressure: Uneven sleep surfaces create sensitive spots under areas of the body that don’t receive as much support as others. Over time, this can lead to aches and pains in the neck, shoulders, lower back, and hips, as well as added pressure points.
  • Hot sleeping: With innersprings and hybrids, sagging comfort foams can restrict the passage of air through the coil layers. The mattress may sleep hotter as a result.
  • Higher noise potential: Deteriorating springs are more likely to squeak and creak when bearing weight. Wear and tear does not affect the noise potential of all-foam or all-latex mattresses as much, since these beds are designed to be virtually silent.
  • Bad for sex: Peaks and valleys can lead to discomfort and awkward movements during sex, according to couples.

Sagging mattresses have more serious implications, as well. As the surface becomes more uneven over time, it may cause problems with sleep onset (falling asleep) and sleep maintenance (remaining asleep). Many sleepers develop insomnia symptoms as a result. People may also experience sleep apnea – a sleep disorder characterized by temporary loss of breath during sleep – if the sagging affects how their neck and shoulders are positioned; excessive head and neck elevation can lead to airway blockage, a leading cause of apnea symptoms.

According to most sleep experts, sagging and indentations that measure at least 1 inch deep are associated with more sleeper discomfort and poorer sleep quality that sag spots that measure less than 1 inch deep. Per the mattress warranty, many manufacturers will replace or repair beds with significant sagging. In the next section, we’ll go over some mattress warranty basics.

Sagging and Mattress Warranty Considerations

Sagging is one of the most widely recognized mattress defects. The vast majority of mattress warranties include specific measurements that qualify as defective sagging. For most warranties, this measurement is 1 inch or deeper. However, these measurements may range from 0.5 to 2 inches, depending on the manufacturer.

Whichever measurement is used, the warranty will not recognize sagging as a defect if it does not reach this depth. Such sagging is considered normal softening of mattress materials resulting from typical wear and tear. Mattress warranties never repair or replace a mattress because its owner is no longer satisfied with the bed’s firmness or comfort level. Additionally, most warranties list specific guidelines for proper foundational support, including acceptable materials, the number of legs required for each size, and the maximum allowed distance between slats. Failure to meet these foundation conditions may result in damage to the mattress, which will void the warranty in most cases.

If a mattress has sagging that reaches the warranty’s prescribed depth, then the owner should file a warranty claim. The process for filing a claim varies by warranty, but in most cases owners must contact the company and submit photographic evidence of the sagging; measurements in the photo indicating the defect are recommended. Owners usually need to provide their bed’s tag number, as well; removing this from the bed at any point will void the warranty.

When filing a warranty claim, be sure to see whether the warranty is in a nonprorated or prorated coverage period. During nonprorated coverage, customers do not pay any additional costs – apart from shipping and handling charges – to have their defective mattress repaired or replaced. During prorated coverage, owners must pay a certain percentage of the bed’s original price; this percentage is normally multiplied by the number of years of ownership.

For example, let’s say a $1,000 mattress has a 20-year warranty with the first 10 years nonprorated coverage and the last 10 years prorated. During prorated coverage, owners must pay 5% of the bed’s original price for each year of ownership. This means that when the prorated phase kicks in during year 11, owners must pay 55% of the original price (5% x 11 years). During year 12, they pay 60% (5% x 12 years); this continues until year 19, one year before the warranty expires, when owners pay 95% (5% x 19 years).

Most 10-year mattress warranties are entirely nonprorated. Warranties exceeding 10 years in length are often partially prorated, and may include only two or three years of nonprorated coverage. Before filing a claim, check the warranty schedule to make sure the costs won’t be too high to replace the mattress – though in most cases, owners save some money compared to buying the same mattress new at full price. It’s also worth noting that the average mattress needs to be replaced after seven years of nightly use, meaning warranties beyond 10 years are often unnecessary.

How to Fix a Sagging Mattress

Since filing a warranty claim may not be the most cost-effective way to repair mattress sagging, owners are encouraged to first try one or more of the following measures:

Solution #1: Rotate the Mattress

Rotating a mattress on a regular basis is a good idea whether or not sagging has occurred. Simply turn the mattress 180 degrees, so that the area that previously served as the head of the bed is now the foot and vice versa. This helps the mattress recover its overall shape, especially in sag spots where the sleeper’s heaviest areas usually rest.

Rotating a mattress every six months is highly recommended – and be sure to seek assistance if the bed weighs more than 90 pounds. Never flip a mattress onto its inverse side unless it is a specialized flippable design with dual comfort layers.

Solution #2: Use a Mattress Topper

A mattress topper is an individual layer of cushioning that is placed on top of a mattress to adjust the firmness. Thicker toppers may also fill in sag gaps and create a more even sleep surface. Toppers usually measure anywhere from 2 to 5 inches thick; thicker models cover sagging more effectively than thinner ones.

Common topper materials include memory foam, convoluted polyfoam, latex, wool, and down/feathers. Some toppers also provide extra cooling for hot sleepers.

Solution #3: Buy a New Foundation

Foundations are often partially – if not fully – to blame for sagging mattresses. An insufficient number of legs can cause sagging, particularly for Queen and larger sizes. Most warranties require owners to support these sizes with foundations that have at least six legs, including a center support leg for added reinforcement.

Slats with gaps measuring 3 inches or wider can also cause the mattress to sag in these spaces. Additionally, foundations – like mattresses – deteriorate over time and need to be replaced, so exceptionally old foundations may also lead to sagging. Make sure to check the mattress warranty for specific guidelines before purchasing a new foundation.

Solution #4: Block the Slats with Plywood

For sleepers with slatted bases, using plywood can be a low-cost fix for sagging beds. For best results, place a thin sheet of plywood (1 inch or shorter) on the foundation so that all slats are covered; measure and cut the plywood beforehand to match the foundation and mattress. If the plywood is sturdy and positioned correctly, it will correct some of the sagging that occurs due to gaps between the slats.

However, plywood is not ideal for some because it minimizes airflow at the bottom of the bed, which can cause the surface to sleep hot and cause mold and mildew to accumulate. Plywood won’t permanently fix sagging, either, but it can be an effective temporary measure.

Solution #5: Pad Sag Spots with Pillows

Pillows placed over gap spots can correct the uneven surface to an extent. This is especially true for pillows with good shape retention, such as memory foam and latex models. Many sleepers also enjoy sleeping with bolster pillows beneath their back, hips, and legs. However, this does not fix the sagging and may not be as effective as the other measures listed above.

Step #6: File a Warranty Claim

If none of the solutions above seem to address the sagging issue, then filing a warranty claim may be the owner’s best option. Contact the manufacturer to initiate the claim and proceed as directed.

Additional Resources

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