How to tell if a mattress is defective: Signs, inspection, and warranty claims

September 30, 2025 •

4 min read

According to the Sleep Foundation, a mattress warranty protects consumers from manufacturing defects and flaws in craftsmanship. Learning how to tell if a mattress is defective can save you from poor sleep and potential pain, and help you determine if you are eligible for a repair or replacement under warranty.

Quick Summary

This guide details the key signs of a defective mattress, from physical flaws like excessive sagging and broken coils to performance issues like noise and body pain. It explains how to inspect your mattress, distinguish defects from normal wear and tear, and navigate the warranty claim process.

Key Points

Identify Physical Flaws: Check for excessive sagging, lumps, or visible damage like broken coils and split seams, as these are common signs of manufacturing defects.
Recognize Performance Issues: Listen for unexplained squeaks or creaks, and pay attention if you start waking up with persistent aches and pains, which can signal a broken internal structure.
Distinguish Defects from Wear: Understand that warranties cover manufacturing flaws that appear prematurely or excessively, not gradual degradation or minor softening that occurs with normal aging.
Inspect Your Foundation: A proper foundation is crucial for mattress longevity. Always check your bed frame or box spring for sagging or damage, as inadequate support can void your mattress warranty.
Understand Warranty Terms: Read your warranty carefully to know what is covered, the minimum sagging depth for a claim, and what actions (like staining or removing the tag) could void your coverage.
Properly Document Claims: When filing a warranty claim, you will need to document the defect with photographs, including any sagging measurements, and provide proof of purchase using your original receipt.

Recognizing the Signs of a Defective Mattress

Your mattress is a significant investment in your health, but sometimes manufacturing defects can cause problems that affect your sleep and well-being. Identifying a defect early is crucial for exercising your warranty rights. Beyond general discomfort, specific physical and performance issues can point to a flawed product.

Visible Physical Flaws

Excessive Sagging: While all mattresses eventually soften and develop some impression over time, excessive or premature sagging is a common sign of a defect. A premature sag might be visible soon after purchase. Warranty policies usually specify a minimum sagging depth, often between 0.75 and 1.5 inches, that must be reached before a claim is covered. This kind of sinking indicates a structural issue rather than normal wear.
Visible Lumps or Indentations: If you notice prominent lumps, uneven areas, or permanent indentations that don't bounce back, the internal materials may be bunching or breaking down. In foam mattresses, this can indicate premature compression or degradation of the foam layers.
Broken or Bent Coils: For innerspring or hybrid mattresses, broken, bent, or protruding coils are a clear sign of a manufacturing defect. These can cause discomfort, uneven support, and can even tear through the fabric.
Split or Torn Seams: Unraveling stitching or split seams are often covered by warranty, as they are considered a flaw in craftsmanship. Inspect the edges and corners of the mattress carefully for any signs of separation. Ripped handles are another sign of a structural issue.

Performance-Related Problems

Increased Noise: A new mattress should not be noisy. If you hear squeaking, creaking, or popping sounds when you move, it could indicate broken springs or internal components rubbing against each other. This can lead to restless nights and disturbed sleep.
Body Pain: Waking up with new aches or stiffness in your back, neck, or shoulders is a major red flag. A defective mattress that fails to provide proper support will throw your spine out of alignment, causing persistent discomfort. If you sleep better on a different bed, like at a hotel, your mattress is likely the problem.
Changes in Comfort: If your mattress suddenly feels too soft, too firm, or develops uncomfortable pressure points long before its expected lifespan, it may have a defect. This is different from a comfort preference; this indicates a breakdown of the internal support system.

Defective Mattress vs. Normal Wear and Tear

It is important to differentiate between an actual defect and the normal aging process of a mattress. Warranties typically do not cover normal wear and tear.


Feature	Manufacturing Defect	Normal Wear and Tear
Sagging	Occurs prematurely and exceeds the warranty's specified depth (e.g., >1.5 inches).	Gradual, minor depressions or indentations that develop over years of use.
Structural Integrity	Broken coils, split seams, or cracked foam evident early in the mattress's life.	Small imperfections, minor compression, or gradual softening over many years.
Noise	Unexplained squeaks or creaks from internal components.	Some noise is expected as a mattress ages, but constant or loud noises are not normal.
Stains/Damage	Not applicable; most warranties are voided by stains.	Owner-inflicted damage like rips, burns, or spills is never covered.

How to Conduct Your Own Mattress Inspection

If you suspect a defect, a thorough inspection can help you build your case for a warranty claim. Here are the steps:

Strip the Bed: Remove all bedding, mattress protectors, and pillows to get a clear view of the mattress surface.
Visual Assessment: Examine the entire surface and sides for any visible issues like lumps, unevenness, split seams, or tears. Look at the corners of a boxed mattress to ensure the foam has fully expanded and filled out.
Pressure Test: Press down firmly with your hand on different areas of the mattress. The surface should spring back quickly and evenly. Any areas that remain compressed or feel excessively soft could indicate a problem with the internal materials.
Sag Measurement: To prove a sagging claim, use a straightedge or a taut piece of string stretched across the mattress surface from one side to the other. Measure the distance from the string to the deepest point of the indentation. Take photos of this measurement as proof for your claim.
Check the Foundation: Always inspect your bed's foundation or box spring for any damage like bowing, cracks, or broken slats. An improper or damaged foundation can cause premature sagging and may void your warranty.

How to File a Warranty Claim

If your inspection confirms a potential defect, here’s how to proceed with a warranty claim, based on information from the Sleep Foundation:

Gather Documentation: Locate your original receipt and the mattress's "law tag," which is a permanent, white tag containing manufacturing details. Never remove this tag, as it can void your warranty.
Read the Warranty: Review the specific terms and conditions of your warranty. Pay close attention to what is covered, the minimum sagging depth, and any actions that could void the warranty.
Prepare Evidence: Take clear photographs of the defect, including your sagging measurement. The manufacturer may also require an inspector to verify the claim.
Contact the Manufacturer: Reach out to the retailer or manufacturer where you purchased the mattress. Explain the issue clearly and provide the documentation you have gathered. Follow their specific instructions for filing the claim.
Follow Through: Be patient and persistent. If your initial claim is denied, ask for a written explanation and review your warranty documentation again to ensure you haven't missed any details. If necessary, you can contact consumer protection agencies for assistance.

Conclusion

Knowing how to tell if a mattress is defective is the first step toward getting a good night's sleep. By carefully inspecting your mattress for visible flaws, listening for unusual noises, and addressing any new aches or pains, you can determine if a manufacturing defect is present. Documenting your findings and understanding your warranty terms will put you in the best position to file a successful claim and get the proper support you need for a restful night.

Frequently Asked Questions

A defective mattress has manufacturing flaws, like excessive sagging beyond a specified depth, that appear prematurely. Normal wear and tear refers to the gradual softening and minor indentations that occur naturally over many years of use and is typically not covered by a warranty.

Remove all bedding and lay a taut string or long, straight object across the mattress. Measure the distance from the string to the deepest point of the indentation. Most warranties specify a minimum depth, such as 1 to 1.5 inches, that must be exceeded to qualify as a defect.

Yes, in most cases, any stains, spills, or other types of soiling will void a mattress warranty for hygiene reasons. Always use a mattress protector to prevent stains and keep your warranty valid.

Yes, a defective mattress that lacks proper support can lead to poor spinal alignment and result in aches and pains, especially in the back, neck, and shoulders. Waking up sore or stiff is a key indicator that your mattress may be the problem.

An inadequate or broken foundation, like a bowed box spring or insufficient slats, can cause a mattress to sag prematurely and mimic a defect. Manufacturers often specify the required support in their warranty terms, and improper support can void your coverage.

For a bed-in-a-box, you should allow at least 48 hours for it to fully expand after unpacking. If it still has visible gaps or uneven corners after this period, it could indicate a manufacturing defect.

No, removing the law tag, which contains essential manufacturing information, almost always voids the mattress warranty. It is crucial to leave this tag attached to your mattress for the duration of the warranty period.