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Why Your Memory Foam Mattress Is Sagging (2027)
Why memory foam mattresses sag and what to do: foundation fixes, rotation, and when to file a warranty claim.
A developing dip in the middle of your mattress is the most common memory foam complaint, and it has a few distinct causes with different fixes. This guide walks through diagnosing the problem and the fixes in order of effort, from free to warranty claim.
The mattress dips where you sleep
Rotate the mattress 180 degrees head-to-foot every 3 to 6 months. This redistributes wear across the surface and is the single most effective free fix. Do not flip it: most memory foam mattresses have a designated top layer and flipping ruins the comfort design.
The foundation is the real culprit
Check your slats. Memory foam needs support every 3 inches at most; wider gaps let the mattress sag between slats, which looks like a mattress defect but is a frame problem. Add a bunkie board or plywood sheet over wide slats for an immediate fix.
The mattress sleeps in a permanent trough
Measure the impression with no weight on the bed. Most warranties define a defect as a visible dip deeper than 1 to 1.5 inches. If yours qualifies, photograph it with a straight edge across the dip and file a warranty claim with the manufacturer.
It felt great for a year, then softened
Some softening in the first months is normal break-in, not a defect. If comfort has genuinely degraded after years of use, a 2 to 3 inch firm mattress topper can extend the bed's life by a year or two, but plan for replacement: most foam beds last 7 to 10 years.
Questions, answered
How do I know if sagging is covered by warranty?
Measure the unloaded impression against the warranty's depth threshold, usually 1 to 1.5 inches. Document with photos showing a straight edge bridging the dip.
Will rotating really help?
Yes, for uneven wear. It will not fix foam that has structurally broken down, but it evens out the normal compression patterns of nightly use.
Can a topper fix a sagging mattress?
Temporarily. A firm topper bridges minor dips, but it cannot restore failed foam underneath. Treat it as a bridge to replacement, not a cure.