Can I make my mattress firmer? Yes − here's how

I asked sleep scientists and mattress manufacturers how to make a mattress firmer for more supportive sleep

Tempur-Adapt Tempur-Topper on a mattress with a nightstand either side against a white wall.
(Image credit: Tempur-Pedic)

Q: I have a soft mattress and I think it might be giving me lower back pain. Can you make a mattress firmer or do I need to replace it?

This is a snippet from an email I received recently. It's a good question, and it got me thinking about all the ways you can make a mattress firmer. You could reinforce a soft, sagging mattress with a firm mattress topper or place a piece of plywood between your mattress and your bed base for consistent support. Turning your mattress is the quickest and easiest way to make it feel firmer without spending a cent.

As H&G's resident Sleep Editor, I lead a team of expert testers in the search to find the world's best mattress. We sleep on mattresses for months, if not years, before we write our initial reviews, so we've learned to spot the signs of wear and tear. We've seen even the best firm mattress start to sag after years of nightly use. We've picked up a few tips and tricks to make a mattress firmer for more supportive sleep and we want to share our hard-won wisdom with you.

Can I make my mattress firmer?

I asked sleep scientists and mattress manufacturers to share their secrets to make a mattress firmer so that you can sleep deeper overnight and feel looser in the morning. As Tempur-Pedic's Thomas Høegh Reisenhus points out, 'A quality mattress is more than the difference between a good night's sleep and a bad one. It's the difference between enjoying good mental and physical health versus struggling with long-term health and performance challenges.'

1. Invest in a firm mattress topper

Avocado Mattress Topper on a bed beneath a window looking out onto the city.

(Image credit: Avocado)

One of the best mattress toppers could toughen up a soft, sagging mattress for a fraction of the price of a brand-new bed.

In terms of materials, you're looking for a firm mattress topper that's filled with natural latex or high-density memory foam. I specify 'high-density' because you don't want the soft, squishy stuff. You need firm, supportive foam to mold to the shape of your body without letting you sink into the mattress. The density of memory foam is measured in pounds of foam per cubic foot: the denser the foam, the more supportive it feels. I suggest 5lb memory foam.

Now, the denser the foam, the more it might trap heat. That could prove problematic for hot sleepers living in warmer climates. Not to worry: you can find cooling mattress toppers that are plenty supportive. Keep an eye out for memory foam mattress toppers injected with cooling gel to dissipate heat and wick moisture.

For natural cooling and springy support, I recommend a latex mattress topper. 'Latex is a great mattress topper material since it has such responsive support,' explains Jin Chon, co-founder of the luxury bedding brand, Coop. 'Latex is a material that you can sleep on, unlike low-density memory foam, which sinks.' Jin says that a firm mattress topper should help to distribute weight evenly across the mattress and prevent your pressure points from sinking. 'A thicker mattress topper is better than a thin one,' she adds: 'you want three inches or thicker.'

2. Turn your mattress

A Casper mattress on a bed beside a Casper delivery box.

(Image credit: Casper)

Take a good look at your mattress and map out the lumps and bumps. Consider whether the whole of your mattress feels soft and sagging or only certain areas. It might be that specific zones of your mattress are under considerable strain, leading to sagging and loss of support. Think about it: if you tend to sleep in the same section of your mattress each night, it's no wonder that this section will start to lose support faster than the bits of the mattress you don't touch.

'Over time, the materials in your mattress start to compress and break down, making it less supportive, explains mattress manufacturer Hafiz Shariff. 'Flipping or rotating your mattress can help to redistribute those materials and restore some of the firmness.'

You should only flip your mattress if it's double-sided: that is, if the mattress construction is roughly the same on top as it is at the bottom. A classic innerspring is a good example of a double-sided mattress. Otherwise, I suggest you rotate your mattress.

I asked an expert panel of mattress manufacturers: 'how often should you turn a mattress?' Best practice is once a quarter so that you can distribute wear and tear evenly across the mattress.

3. Check the foundations

A mattress on the Saatva Adjustable Base Plus against a white wall.

(Image credit: Saatva)

If you tried turning your mattress, but it hasn't made much of a difference, then the problem might not be your mattress, after all. Perhaps the loss of support is coming from your bed base.

Even the best bed frames can become loose and move over time. When you're in bed at night, listen out for squeaking and creaking and feel around to spot the sagging. To get a better look at your bed base, lift up your mattress and inspect for broken or cracked slats. If you've got an adjustable bed, play around with the controls to create a level, supportive base.

4. Place a plywood board beneath your mattress

Layla Hybrid Mattress beside a Layla mattress box against a gray wall.

(Image credit: Layla)

This is a trick I've picked up from mattress testing. If your mattress is too soft, but you don't want to buy a new mattress or a new foundation, then you could use a plywood board as a makeshift mattress base. It's an easy, affordable way to create a solid, flat surface and lend more consistent support to your mattress.

You could cut a piece of plywood if you're feeling handy or buy a wooden mattress support from Amazon. Don't worry too much about the thickness of the wood – an inch of plywood could easily do the job. Place the board between your mattress and your bed base, making sure it's sitting in the center.

FAQs

Will a firm mattress help my back pain?

A firm mattress might help with your back pain. A firm surface could help to distribute your weight evenly across the mattress, stopping your pressure points from sinking in and promoting proper spinal alignment. Still, even the best firm mattress can't cure back pain: that's something you should take up with a chiropractor.

Can a firm mattress cause back pain?

A firm mattress could cause back pain if it pushes on your pressure points and throws your spine out of alignment. This would be a particular problem for side sleepers, who need a mattress with a bit of give. It's all about finding the best mattress firmness for you: sufficiently supportive, without feeling inflexible.

Final thoughts

If you've tried everything, and you still can't sleep comfortably on your soft mattress, then it's time to invest in the best firm mattress. We've tried and tested classic innersprings, high-tech hybrids, and high-density memory foam models to relieve pressure, ease pain, and keep your spine aligned.

Emilia Hitching
Sleep Editor

Emilia is our resident sleep writer. She spends her days tracking down the lowest prices on the best bedding and spends her nights testing it out from the comfort of her own home – it's a dream job. Her quest to learn how to sleep better has taken her all around the world, from mattress factories in Arizona to sleep retreats in Scandinavia. Before she joined Homes & Gardens, Emilia studied English at the University of Oxford. She also worked on the other side of the aisle, writing press releases for regional newspapers and crafting copy for Sky.