Why is my bed sinking on one side?

If you notice that your mattress is sagging or sinking on one side, there are a few potential causes for this common problem. The sinking could be the result of normal wear and tear, an uneven foundation, improper mattress support, or an issue with the mattress itself.

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What causes a mattress to sink on one side?

Here are some of the most common reasons why a mattress may start to sink or dip on just one side:

Normal wear and tear – Over time, mattresses naturally soften and sink in a bit. This can happen unevenly if the mattress receives more use on one side. For example, if one person in a couple weighs significantly more than the other, their side may start to sag first.

Uneven foundation – If the bed frame or foundation is uneven, unstable, or sagging, it can cause the mattress above to sink as well. This issue is more common with older foundations or poorly constructed frames.
Improper support – Mattresses need adequate support from both the foundation and bed frame. If the box spring, slats, or bed frame beams are spaced too far apart, it allows the mattress to dip between the gaps.
Internal mattress issue – In some cases, the sinking may result from an issue inside the mattress itself. If the support layers deteriorate or materials shift unevenly inside, one side could start to sink.

How can I fix a sinking mattress?

Here are some tips to troubleshoot and fix a mattress that is sinking or dipping on one side:

Inspect the mattress foundation

Check that the foundation or box spring is evenly supported from below. Bed frames with a center support and solid headboard/footboard tend to provide the most stable base. Make sure the frame is sturdy with no loose joints or broken slats.

For platform beds, ensure the slats are no more than 3 inches apart and that none are broken, loose, or sagging. Add extra slats or plywood between the gaps if needed. Shims can help level any slight dips in the foundation.

Add reinforcement

Installing a mattress topper or pad can help provide extra support and fill in any uneven sinking spots. Look for a firm or extra firm topper at least 2-3 inches thick. You can also try placing plywood between the foundation and mattress.

Rotate the mattress

Rotating your mattress 180 degrees every 3-6 months can help prevent uneven wear. It allows you to sleep on alternating sides so no single area gets excessive pressure.

Replace the mattress

If the dip or sinkage is severe and other fixes don’t work, it may be time for a new mattress. Look for one with an innerspring coil support system and high-density foams that offer good sturdiness and edge support.

When should I replace my mattress?

As a general guideline, most mattresses should be replaced every 7-10 years. But there are some signs that indicate your mattress has reached the end of its usable life and needs to be replaced sooner:

Visible sagging, sinking, or impressions deeper than 1.5 inches
You regularly wake up with aches and pains

The mattress makes noise (creaking, crunching)
You feel the coils or wires beneath the surface
Allergy symptoms have increased

It’s difficult to turn or move on the mattress

If you’re noticing these issues or your mattress is over 10 years old, it’s probably time to start mattress shopping. An old, worn out mattress won’t provide adequate comfort and support for restful sleep.

How do I choose the best replacement mattress?

Here are some tips for selecting a new mattress if your old one can’t be salvaged:

Shop in person to test out mattresses. Lie on each one for at least 10-15 minutes.
Bring your sleeping partner to test mattresses together.
Ask about return policies in case the mattress doesn’t work out.

Consider your sleep position and look for a mattress suited to it. Side sleepers need more pressure relief while back sleepers need more lumbar support.
Don’t skimp on quality – expect to spend $1000 or more for a good mattress.
Compare materials and durability. Look for advanced foams or hybrid options.

Don’t feel pressured by sales pitches. Take your time with the decision.

Investing in a high quality, supportive mattress can help provide restful sleep for many years. Take time to test different brands and materials until you find “the one” for your best sleep.

How can I prevent my new mattress from sinking?

Use these proactive tips to help keep your mattress in good shape for as long as possible:

Use a firm, sturdy bed frame with a center support beam and solid headboard.
Make sure the foundation is equally supportive – check for broken slats.
Don’t jump or stand on the mattress – this can compress foam and damage coils.

Rotate your mattress 180 degrees every 3-6 months to evenly distribute wear.
Vacuum the mattress surface regularly to prevent buildup of dirt, dust mites, and allergens.
Consider a mattress protector to shield from spills and stains.

Don’t let kids or pets roughhouse directly on the mattress.

With proper care and maintenance, a quality mattress should stay in good condition and resist sagging or sinking for many years.

What causes uneven wear on a mattress?

There are several reasons why a mattress may wear unevenly and begin to sink or sag more on one side:

Improper support – An unstable foundation that flexes or shifts can cause uneven mattress wear. Make sure slats are no more than 2-3 inches apart.
Poor frame construction – A bed frame that lacks center support or sturdy corner legs allows sagging in the middle of a mattress.
Excess weight – If a heavier person sleeps on one side of the bed, it will compress down more and lead to uneven wear.

Sleeping in the same spot – Regularly sleeping in the exact same spot concentrates pressure and wear in a particular area.
Not rotating – Failing to rotate your mattress can result in uneven softening on each side.

To prevent uneven wear, use a supportive foundation and frame, rotate the mattress regularly, and try to sleep in different spots rather than the exact same position every night.

What kind of foundation is best for a mattress?

The best type of foundation for your mattress depends on the mattress type:

Mattress Type	Recommended Foundation
Innerspring	Box spring or solid platform bed with slats no more than 3 inches apart.
Memory foam	Solid platform bed or adjustable base.
Latex	Solid platform bed or slatted foundation with minimal flex.
Hybrid	Box spring or solid platform bed.
Air bed	Matching air bed chamber or solid platform.

In general, look for a foundation that offers sturdy support across the entire mattress surface. Avoid foundations that dip significantly or feel unstable.

When should I rotate or flip my mattress?

Here are some tips for rotating and flipping mattresses:

Rotate your mattress 180 degrees every 3-6 months to prevent uneven wear and softening.
Alternate the head and foot placement when rotating.
Only flip one-sided mattresses, not two-sided ones.

Flip a one-sided mattress over every 1-2 weeks for the first 3 months to distribute wear.
After that initial break-in period, flip a one-sided mattress 1-2 times per year.
Foam and latex mattresses may not need flipping but still require rotating.

Mark your mattress with tape or stitching to track rotation.

Consistently rotating your mattress helps maintain even comfort and support across the surface. Flipping over occasionally also extends the usable life of a single-sided mattress before replacement is needed.

How can I make a sunk-in mattress more comfortable?

If your mattress is starting to sag or feel less comfortable, there are a few easy ways to help:

Add a mattress topper – Memory foam or feather toppers can help fill in depressions.
Flip or rotate mattress – This helps prevent uneven wear in one spot.
Add reinforcement – Try using plywood between the box spring and mattress.

Switch sides – If you sleep with a partner, swap sides of the bed.
Adjust your sleep position – Placing pillows strategically under knees or arms takes pressure off sunk spots.

While these tips can help temporarily, a new mattress may be required if sagging and sinking issues become severe. Look for signs like visible indentations deeper than 1.5 inches or uncomfortable pressure points.

Can I fix a sagging mattress without replacing it?

There are a few DIY solutions you can try before replacing a sagging mattress:

Rotate the mattress frequently to redistribute wear evenly.
Use boards or plywood between the box spring and mattress to reinforce support.

Place the mattress directly on the floor to eliminate foundation issues.
Add a mattress topper to provide a buffer over impressions.
Repair broken coils by retying or replacing loose springs.

Fill depressions with tennis balls covered in socks.

However, if these options don’t resolve significant sagging and the mattress is over 7 years old, replacement may be the best permanent solution. Prevent sagging in a new mattress by choosing high-density foams, rotating regularly, and using on a solid foundation.

At what point is it better to replace a mattress than fix it?

There are a few clear signs that indicate when it’s time to replace a mattress rather than attempting fixes:

Sagging or impressions deeper than 1-1.5 inches
Visible cracks, tears, or exposed coils/wires
You consistently wake up with stiffness or soreness

Allergy symptoms have increased
You feel springs or coils beneath the surface
The mattress is over 10 years old

Rotating and flipping provides no improvement

While quick fixes like toppers may temporarily help issues like mild softness or sagging, they are not long-term solutions. At a certain point, excessive wear, deterioration of materials, and lack of support means it’s time to invest in a new mattress.

What household items can fix an uneven mattress?

You may be able to temporarily address uneven spots and sagging in a mattress using these handy household items:

Tennis balls – Place 2-3 balls in a sock and position under sunken areas overnight.
Boards or plywood – Slide wood between the box spring and mattress to reinforce support.
Furniture pads – Use self-adhesive pads under sunk spots to add cushioning.

Pool noodles – Cut to size and place under mattress corners or edges to prevent sliding.
Bubble wrap – Use sheets of bubble wrap to build up and level out depressions.
Yoga blocks – Strategically position under saggy areas for added lift.

While these do-it-yourself tips can help temporarily, replacing weak foundations, rotating the mattress, or investing in a new one are longer term solutions.

What are signs that a new mattress is poor quality?

Here are some red flags that may indicate a lower quality mattress:

Sags visibly after only a few months of use

Has a short warranty period (less than 10 years)
Contains low density polyurethane foam (under 1.8 lbs/cu.ft)
Feels excessively soft initially in the store

Contains fiber padding rather than memory or latex foam
Is sold only online or via retailers with flexible policies
Is imported from overseas with limited quality control

Has an unnatural chemical smell when new

Quality indicators to look for include high density foams, hybrid spring systems, advanced cooling materials, robust edge support, and long in-home trial periods. Reputable retailers and brands also provide at least 10 years of warranty coverage.

What materials make the most supportive and durable mattress?

These mattress materials offer the best combination of support, comfort, and durability:

Pocketed coils – Individual fabric-wrapped springs provide contouring support and minimize motion transfer.
Latex – Natural or synthetic latex foam is resilient, breathable, and durable.
Memory foam – Body-contouring viscoelastic foam relieves pressure points.

Hybrid – Coils combined with memory or latex foam offer great support.
High density foams – Polyurethane over 1.8 lbs/cu.ft has better longevity.
Wool – Natural wool padding regulates temperature and resists body impressions.

The highest quality mattresses often blend materials like latex over pocket coils or memory foam with an inner coil support system. This provides both comfort and long-lasting structure.

Conclusion

A mattress that sags significantly on one side is usually a sign that the mattress is worn out or is not receiving adequate support. Normal use, improper foundations, and uneven weight distribution are common culprits. While temporary fixes like toppers may help, rotating and ultimately replacing the mattress are longer-term solutions. Investing in a supportive mattress foundation and taking steps to distribute wear evenly can help extend the lifespan of a new mattress.