Symptoms
- Visible dip or valley where you usually sleep
- Waking up with back or hip pain
- Rolling toward the middle of the bed
Likely causes
- CommonFoam compression from years of body weight in the same spotMemory foam and poly foam lose their ability to rebound over time.
- CommonWorn-out innerspring coilsCoils lose tension in the areas that bear the most weight.
- PossibleInadequate or sagging bed base/foundationA worn box spring or missing center support can make a mattress sag prematurely.
- CommonMattress past its expected lifespanMost mattresses are designed to perform well for about 7–10 years.
What to do
- Check the bed frame and foundation for broken slats or a missing center support leg.
- Rotate the mattress head-to-foot every few months if the manufacturer allows it (not all foam mattresses should be flipped).
- Add a mattress topper to redistribute pressure and reduce the feel of a shallow sag.
- Measure the depth of the dip with a straight edge and ruler; over 1.5 inches is generally considered significant sag.
- Check the mattress warranty, since many cover sagging beyond a certain depth within a set number of years.
- If the mattress is old or the sag is severe, plan for replacement rather than continued patching.
Tools and parts
- Straight edge or level
- Ruler
Mattress topperSearch: “supportive mattress topper for sagging bed”
Bed frame center support legSearch: “bed frame center support leg kit”
When to call a pro
If the mattress is under warranty, contact the manufacturer or retailer directly rather than attempting repairs, since altering it may void coverage.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.