How to Fix Memory Foam Mattress Dips, Sags and Soft Spots

Quick answer: How to fix memory foam mattress problems depends on the cause. Rotating head to foot (never flipping) helps soft spots from normal wear. A dip caused by a weak base is fixed by fixing the base. A deep sag is a warranty question: Tempur-Pedic, for example, covers indentations deeper than 0.75 inches. A topper only hides it.

Here’s the uncomfortable truth first. Foam that has broken down can’t be restored. Casper puts it plainly: sagging and wear come from foam cells breaking down, and flipping a foam mattress won’t refresh it.

So “fixing” a memory foam mattress really means three things. Slowing the wear, removing whatever is causing it, and knowing when to file a claim or replace it.

Why It Happens

Work out which of these you’re dealing with before you spend anything:

1. Normal softening. Memory foam gets softer with use. Tempur-Pedic’s warranty treats a normal increase in softness as expected, not a defect.
2. Body impressions. Nectar notes that memory foam forms body impressions where pressure is concentrated, so sleeping in the same spot every night wears a shallow dip there.
3. A weak or wrong foundation. Missing center support, too few legs, or a frame that flexes lets the mattress sink with it.
4. A real defect. An indentation deeper than the warranty threshold, measured with no one on the bed.
5. Old age. The Better Sleep Council says a mattress set that’s 7 years old has generally reached the end of the line.

And one that isn’t wear at all: a brand-new boxed mattress that still looks flat or lumpy may not have finished expanding. See memory foam mattress not expanding for that.

How to Fix Memory Foam Mattress Sagging, Step by Step

Step 1: Measure the Dip

Strip the bed. Lay a straight edge, like a long level or a broom handle, across the low spot from one side to the other, and measure the gap at the deepest point.

Do it with nobody lying on the mattress. Tempur-Pedic’s warranty measures indentations “without weight or pressure applied.” Check your own brand’s terms for its method. Write the number down and take a photo. You’ll want both if you contact the manufacturer.

Step 2: Check the Foundation

This is the step I’d never skip, and I think it’s the most important. A mattress can only be as flat as what’s under it.

Tempur-Pedic’s warranty is a good benchmark. It requires a matching foundation or adjustable base with a proper frame, and the frame must include a center support. For queen, king and California king sizes, it asks for at least 5 to 6 legs; for twin and full, at least 4.

Things I’d look for:

• a center rail or center legs that have dropped, bent or gone missing
• slats that are cracked, bowed or spaced far apart
• a box spring that’s itself sagging

Nectar notes that foundations with fewer than six legs can cause sagging, and that mattresses on slatted bases can sink between the slats. If the base is the problem, fixing it may solve the dip outright. It also matters for coverage: Tempur-Pedic excludes damage linked to an improper frame, foundation or base.

Step 3: Rotate, Don’t Flip

Casper recommends rotating a memory foam mattress 180 degrees every 6 to 12 months, so the head end becomes the foot. That moves your hips and shoulders onto less-used foam.

Don’t flip it. Casper says flipping a foam mattress won’t do anything to refresh it, because the wear is in the foam cells themselves. Check your own brand’s care guide too, since some designs shouldn’t be turned at all.

Step 4: Use a Topper as a Stopgap

A topper can make a mildly dipped mattress more comfortable. Nectar says toppers, usually 2 to 5 inches thick, don’t fix sagging but can reduce its effects by giving you a more even surface.

My take: treat a topper as a bridge, not a repair. On a deep dip, the topper just sinks into the same hole.

Step 5: Skip the Pillow Hack

Stuffing a pillow into the low spot sounds clever. Nectar calls placing pillows in sagging areas a temporary fix and advises against putting pillows under the mattress. I agree with the temporary part.

How to Fix Mattress Dip Problems That Are Covered by Warranty

If your measurement passes the threshold, contact the manufacturer before you buy anything.

Tempur-Pedic’s 10-year limited warranty, for example, covers visible indentations greater than 0.75 inches. The same warranty excludes:

• normal softening of the foam
• changes in how the mattress feels, such as firmness or bounce
• damage from an improper frame, foundation or adjustable base
• damage from liquids, including spills and bodily fluids

That last point is why a mattress protector matters. Tempur-Pedic’s warranty also requires that you keep using the cover that came with the mattress.

Other brands set different thresholds, so read yours. Keep your receipt, your measurement and your photos together.

When to Replace It Instead

The Better Sleep Council suggests checking your mattress for comfort and support twice a year. It lists these signs that it’s time for a new one:

• visible sagging, tearing, holes or damage
• you sleep better somewhere else, such as a hotel
• you wake up stiff or sore, or feel tired after a full night’s sleep
• the mattress is 7 years old or older

If waking up sore keeps happening, mention it to your doctor too. A mattress isn’t the only possible cause.

Casper says beds over 8 years old are “definitely” due for replacement. Browse our mattresses and toppers section when you’re ready to compare options.

Frequently Asked Questions

Can you fix a sagging memory foam mattress?

Not fully. Worn foam can’t be restored. You can slow wear by rotating it, fix a weak foundation, and use a topper as a short-term comfort layer. A deep sag may be covered by warranty.

How do I fix a dip in my mattress?

Measure it with a straight edge and no weight on the bed, check the foundation for missing support, rotate the mattress, then contact the manufacturer if the dip passes the warranty threshold.

Should I flip my memory foam mattress?

No. Casper says to rotate memory foam 180 degrees every 6 to 12 months instead, because flipping won’t refresh worn foam.

How deep does a sag have to be for warranty?

It depends on the brand. Tempur-Pedic’s 10-year warranty covers visible indentations deeper than 0.75 inch, measured with no weight on the mattress.

Will a mattress topper fix a sagging mattress?

No. Nectar says toppers don’t fix sagging, though they can reduce its effects by evening out the surface.

Last updated: November 10, 2026. Sources: Tempur-Pedic 10-year mattress limited warranty, Casper: how often to rotate your mattress, Better Sleep Council: replacing a mattress and Nectar: how to fix a sagging mattress.