Do all foam mattresses sag throughout the night?

Mattress Talk
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Hi all. Newbie here desperate for help.

I have a foam mattress. It says it’s “extra firm” but I toss and turn throughout the night and by the time I wake up I find myself in a depression of 1 or 2". It screws up my back something fierce.

Of course, the foam resets throughout the day and it’s firm enough to use again the next night but the cycle repeats and I’m in a depression again.

I’m persuading myself that there’s no such thing as reliable foam. they’ll all break down like this throughout the night and I’ll be left with a sore back and neck no matter how many I try.

Really I’m this close to just sleeping on my floor at this point. I need the surface to be the same at the end as it was at the start. Is that really not possible in this day and age?

Thank you all in advance for your advice as I struggle with this!

DW

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Hi DW,

I totally get your frustration,sleeping on a mattress that does not hold up through the night can really mess with your back and leave you exhausted. I have been through a similar struggle myself while recovering from neck pain and I learned a few things that might help.

Not all foam mattresses sag like that every night. What you are describing sounds like a lower density or poorly layered foam construction that does not offer lasting support under pressure especially for side or back sleepers. A good high density memory foam or a hybrid mattress usually holds its shape much better overnight and can provide the consistent support you need.

You might also want to look into mattresses with zoned support—these are designed to hold up better in areas where your body needs it most like hips and shoulders without collapsing by morning.

In the meantime, using a firm mattress topper can help even out the surface and reduce that sinking in feeling while you explore better options.

Do not lose hope,there are options out there that stay firm and supportive. You do not have to give up and sleep on the floor.

Hope this helps and wishing you pain-free sleep soon.
Best regards by sana

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Hi dw90125,

Welcome to the Mattress UnderGround.

Well it is sort of a loaded question. What time of foam? What firmness? How thick is the comfort layer. What is the manufacturers definition of extra firm? Do they offer an ILD rating? What support layer is supporting the mattress, it is all foam, or a hybrid. I know you stated foam mattress, but having some specifics would be helpful. What is your height and weight, body type and do you sit up in bed, only sleep, and not work on a laptop, like I do.

What foundation are you using? What is it made of. What brand is the mattress and foundation?

Mattresses are very nuanced. One bad layer on a great mattress can take a mattress down. " A mattress is only as good as it’s weakest layer" This is true for a $500 mattress or a $5000 mattress. A bad or low quality layer or bad foundation, can cause issues with the best of mattresses out there.

Sorry to hear your struggles but, we need a bit more information to help solve the issue. There are certainly different levels of foams. Foams do break down over time, but density, processing, quality control, location of manufacture and manufacturing processes are all critical concerns to be able to answer your issues.

Looking forward to the rest of the vital information, as it does matter.

Maverick

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Hi Maverick.

Well I don’t have a lot of details about the mattress in terms of construction. I know it’s an Ikea Morgedal. That’s about it.

As for me, I’m a “big and tall” kind of guy. 6 feet, 250lbs. Always been a rotisserie kind of sleeper. I start on my side and rotate many many many times throughout the night.

I have a platform foundation. It’s a hard plastic box from an old Sleep Number bed that I got rid of a year ago. It started forming a depression after 10 years and I went with the Ikea because it felt really firm the day I bought it.

Really I just can’t have a depression while I sleep. I’ve considered buying a futon just so I could have something immutable but cushioned under me.

I don’t know if what I need exists out there, but I’m really hoping it does.

Thanks again for your response!

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The first thing I would do is rotate the mattress and place it on the floor and sleep on it to determine if it is the mattress or the foundation. I was working with someone on reddit recently and they were convinced their foundation was great, and it could not have been their issue… Until they placed their phone under the mattress and recorded what was going on under the mattress once he put his body on it while sleeping. His foundation met all the usual specs, 3/4" thick, proper spacing and slat width. The slats were bowed and flexing when he got on the mattress causing the sagging. He was rushing out to HomeDepot to get 1.5" thick slats that he intends to close the spacing and screw into the bedframe. I am waiting to hear if it works for him.

Your Ikea mattress is said to have Foam Layers

  1. Top Layer (Comfort Layer):
  • Material: Zoned polyurethane foam
  • Thickness: ~2.4 inches
  • Density: 2.2 lb/ft³
  • Features: Grooved zones for pressure relief at shoulders and hips
  1. Bottom Layer (Support Layer):
  • Material: Polyurethane foam
  • Density: 1.7 lb/ft³
  • Function: Provides foundational support

The high-resilience (HR) foam layer falls short of the recommended minimum density of 2.5 lb/ft³, and the polyurethane base foam is also below the commonly advised 1.8 lb/ft³ threshold for mattress support. As someone who is on the heavier side (I was over 250 lbs at 6’ tall when I bought my mattress, now down to 220), this is especially important. Heavier individuals typically need even denser foams to ensure proper support and durability. While the shortfall in density might seem minor, it can significantly impact comfort and longevity for larger bodies.

First thing, try the mattress on the floor rotated away from the already sagging area. You do need to consider that the sagging from your sleep number may have been due to the foundation, and when you tried the Ikea in the store or when you first got it home, it will always feel more firm for a while, until all of the nuanced factors start to kick in. Although, I am surprised you actually got 10 years from your SN, consider yourself lucky, unless there were signs of compromise years earlier and you just glossed over it for a while, which happens. I did that with my 11 year old Sealy PosturePedic prior to my purchase of my Brooklyn Bedding Plank Luxe 3/4" - 50lb quilted cover foam, 2" of HD1.8lb 36 ILD foam, and 13.5Gauge firm spring support system 9-9.5/10 firmness. It is a two sided mattress, with a slightly less firmness on the flip side 8-8.5/10, but we use the firmer side.

All of these things matter. Even a 1.5" mismatched loft of your pillow is enough to cause neck, back and should pain when sleeping. This is particularly true the older we get (I am 65). Which is why I generally will ask about height, weight, sleep position and age, when offering suggestions for solving issues.

If the sag seems to recover with the mattress on the floor, that is promising. In addition to sleeping on the adjacent side of the mattress after rotating and placement on the floor. If you dont notice the same sagging, you know the foundation is an issue. If your start sagging the mattress on the floor, it is the foam densities and mattress that is the issue. Furthermore, if the mattress does not sag on the floor, rotate the mattress back if the sag on the original side has recovered. Sleep on it again, on the floor. If it sags again, you know that it was the foundation that may be the initial cause of the sag, but now the mattress has taken on the sag that is not recoverable. So you have to sleep on the rotated mattress and get a new foundation, for as long as that will hang in there, or you may need to consider a completely new system foundation on up.

Sorry about what you are experiencing, but with a little bit of finesse, we can get to the bottom of this.

Maverick

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Hiya Maverick.

Just following up – put the mattress on the floor last night as you suggested. Possibly was the worst night of sleep that I can recall. And I was still sunk into the mattress by the morning with awful back pain.

Seems to me I can rule out the platform at this point. This mattress is shot. So the question returns to – can I trust foam really? I feel like no matter what foam I buy (ILD notwithstanding) I’ll eventually grind a divot into it and I’ll be right back here.

And yet everything I’ve tried - springs, air, foam - all end the same way. A divot in the bed and a sore back.

I want to believe that a solution exists, but I’m quickly losing hope…

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One of the main things we discussed is foam density, and that’s still worth considering. A mattress like the @DLX Premier Hybrid, which uses 2.4lb high-density foam, may offer a noticeable improvement in durability and resistance to deep body impressions and sagging. The general rule is: the higher the density, the more durable the foam, and the slower it breaks down under pressure.

That said, there’s no rule stating you must use synthetic foams at all. In fact you can lean away from foam altogether, there are several brands and builds that may suit you better. For example, @ShovlinMattress in Fanwood, NJ offers traditional builds like their Classic Innerspring, which uses 2.8lb density foam in a flippable, two-sided design. It’s paired with a durable 12.75-gauge coil system and customizable cushioned covers. If you want to avoid foam entirely, their Vegan Mattress is another option, it uses a 13-gauge spring system along with felt support pads and cotton, resulting in a firm, minimal-sag construction with no synthetic components.

Another brand to consider is Shifman right here in NJ. They offer mattresses built with layers of natural materials such as cotton, wool, and in some models, latex. Many of their beds are constructed without synthetic foam altogether, and they tend to focus on durable, hand-tufted builds that resist sagging over time resulting in mattresses that can last 20 years.

Millbrook is a British brand produced in New Jersey by Bedding Industries of America. Their beds use hand-nested coils arranged in a honeycomb design, layered with dense, tufted cotton and with the occasional latex added. These traditional builds tend to provide excellent durability and body support with minimal long-term breakdown.

Having the ability to customize on the fly to target certain needs is a strong point of @EngineeredSleep and their Duo Lift mattress, which is a great foam-free option. Engineered Sleep has a solid reputation for tailoring mattress builds to specific needs, and their Duo Lift system allows for individual side customization using natural materials and robust innerspring support.

It seems like this general direction, toward either very high-density foam or entirely foam-free, natural/hybrid builds, might be the best path forward.

One thing to keep in mind with natural fiber mattresses (especially those using cotton or wool) is that they will develop body impressions over time. These aren’t the same as sagging or painful sinkage, but rather a natural contouring effect as the fibers compress and adapt to your shape. In many cases, that can be a positive thing, as it helps the mattress conform to your body without compromising support. I experienced this with my 3" hand made organic wool topper. It was actually quite comfortable compared to what it appeared on the mattress. The body impressions were quite visable, but offered no discomfort when sleeping on the mattress with the topper.

Some of these mattresses can get up there in price, particularly Shifman, but Shovlin offers some very affordable options with higher density materials and springs that just may close the book on your issues.

It is worth a reach out to them.

So sorry you have to deal with this, but we are going to solve this.

Maverick

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Mav:

Thanks so much. I sincerely appreciate your help and your determination.

I’m willing to try anything, but I find myself confused about what the next move should be. I’m the kind of person that believes there’s no such thing as a failed experiment, but I don’t want to bang my head into a wall either.

I’ll review all of your suggestions here and see if there’s something that might make a good fit for me to try. And I’ll certainly come back with questions!

Truly - thank you again for your time.

Dave

1 Like
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Heya Mav.

One update – I rotated the mattress a second time on the floor and at least I slept a little better. It definitely has a permanent depression in it so no matter what I’ll have to get something new.

All this time afforded me a chance to examine my platform a little more closely. It’s the black plastic box that select comfort / sleep number used to sell with their beds and it has been sturdy for as long as I can remember.

I noticed that the dead center however is a little soft. I guess the four panels meet in the middle and there’s no support in those four corners. So I am able to push down right in the middle and there’s hardly much resistance.

Now I can’t believe that a small spot (maybe 10 sqin) could lead to an entire mattress developing a depression like I’m dealing with, but it does make me think it’s high time for a new foundation after all!

Perhaps I should get that addressed first? I see many simple platforms I can buy for a few hundred bucks and at least restore confidence that I have underlayment support. What do you think?

Seems to me that I should tackle this before I buy any mattress at least. Otherwise I’m just putting a good mattress on a bad foundation, right?

Thanks as always!

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Good morning DW,

James from Shovlin Mattress here. We are located in New Jersey. Sorry I am jumping into the conversation late, I was away on vacation for a few days.

After reading through the previous messages, you seem like a straight shooter, so I am going to give it to you straight.

IKEA mattresses are not good, they use a lesser quality memory foam, which is how they are priced Under $500. For a toddler on a new bunk bed, fine, but for us 240lbs+ guys with back issues, most mattresses will not cut it. This can also ring true for expensive memory foams.

Yes, its probably time for a new platform, but those old school sleep number were pretty sturdy, and while this may be contributing slightly, this is not what is causing the issue with your mattress.

To answer your first question, no, not all foam mattresses sag throughout the night, it just depends on what type of foam and what type of budget you have.

If you have any additional questions or would like to visit our showroom and take a tour of our factory and see how high quality mattresses are made, don’t hesitate to reach out.

James Campbell
Vice President of Sales
908-322-4178

Semper Fi

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Your foundation is the unsung hero of your bedding setup. Many of the TM’s offer options available here, that are solid, well-built foundations. The @MattressFoundations Terra Foundation is a great example, it’s built like a tank.

I recently tried a bedframe/foundation @EuropeanSleep that had all the high level of sturdiness. They were beautifully designed, with headboards, footboards, and side panels available in a variety of woods and finishes. Like the Terra, they were so solid you could probably park a car on them.

Of course, the quality of the wood, the design, and the engineering all contribute to a higher price point. These aren’t your typical $300 foundations or bedframes, they’re high-quality pieces of furniture. That said, they’re not the only option, just a very good one that’s likely to last a lifetime. For example, Big Fig makes a nice basic foundation you would use on your own bed frame.

The foundation plays a crucial role in your overall sleep setup. If you can find a way to include one during this process, it will likely make a noticeable difference in your comfort and long lasting satisfaction.

Maverick

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Hello,
So much stuff here already, so no retread on the other comments. Just wanted to add that polyurethane foams don’t usually recover from actual “wear”, but they do recover from humidity. All foams, and many fills, lose firmness as they become wetter, and then recover as they dry. Ventilation will be key if this is the case, and maybe a mattress with a wool quilt (?). Anyway, just a thought. Hope that is helpful!

1 Like
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Welcome to the forum and I am really sorry to hear about your struggle. You have definitely not alone,many people experience exactly what you’re describing with foam mattresses.

From what you have said, it sounds like your mattress might be made of memory foam, which is known for contouring to the body. While it can feel firm at first, heat and pressure throughout the night can cause it to soften and create that sinkhole feeling you are dealing with. Even some extra firm models can lose support temporarily as the foam warms up.

Here are a few suggestions that might help:

Try a high-density foam mattress – Look for something with a density of at least 1.8–2.2 lb/ft³ or higher. These tend to hold their shape better overnight.
Consider a latex mattress – Natural latex offers great support and resilience. It doesn’t trap heat the same way memory foam does and usually returns to its original shape faster.
Use a firm mattress topper – A high-quality, firm latex or polyurethane topper could add an extra supportive layer and reduce the sinking effect.
Check your base – Make sure your bed base is supportive and not contributing to the sag. Slats should be close together, or consider a solid foundation.
Rotate your mattress regularly – This helps distribute wear more evenly and can improve overall comfort.

Do not give up yet.There are foam or hybrid options that stay supportive all night,you may just not have found the right one yet.

Wishing you better sleep soon.
Best regards by sana