Memory foam mattress topper: a UK buying guide
A memory foam mattress topper is a layer of foam, usually 5 to 10 cm deep, that sits on your mattress and changes how it feels. A good one softens pressure at the shoulders and hips and can make a tired mattress comfortable again for far less than a new bed. Four things decide whether you will like it: depth, density, firmness and how warm it sleeps. Below we cover each, compare the main types, and explain where the Dosaze DreamAlign toppers fit and where something else may suit you better.
What a topper can and can't fix
A topper changes the surface. It can add cushioning to a mattress that feels hard, add firmness to one that has gone a bit soft, and take some wear off the mattress underneath.
It cannot fix a mattress that has collapsed. If there is a dip you can see when the bed is empty, or springs you can feel through the top, a topper will simply follow that shape. In that case the money is better spent on a new mattress.
What to look for
Depth
At 5 cm the change is gentle, enough to take the edge off a firm mattress. Around 7.5 cm is the middle ground most people end up with. At 10 cm or more the feel of the bed changes a lot, the topper is heavier to lift, and you may need deep-pocket fitted sheets.
Density
Foam density is given in kg/m³. Cheaper toppers often use foam around 30 kg/m³, which feels fine at first but tends to flatten sooner. Foam in the 40 to 50 kg/m³ range usually holds its shape longer, though it is heavier and can sleep warmer. Density is not the same as firmness: a dense foam can still feel soft.
Firmness
Soft memory foam lets you sink in and moulds around you. Firm foam holds you nearer the surface. Side sleepers usually want enough give for the shoulder and hip to sink slightly, while back and front sleepers, and heavier people, often do better with something firmer so the hips don't drop too far.
Heat
Traditional memory foam softens with body heat, which is what gives it that slow, hugging feel. It also holds that heat. If you already sleep warm, look for gel infusion, open-cell foam, a convoluted (egg crate) surface that lets air move, or a breathable cover. Your bedding matters too, since a plastic-backed protector or heavy duvet can undo a cool topper.
Size and fit
Standard UK sizes are single 90 x 190 cm, double 135 x 190 cm, king 150 x 200 cm and super king 180 x 200 cm. Some European brands sell a "king" at 160 x 200 cm, so check the measurements rather than the name. Elastic corner straps or a fitted skirt stop the topper sliding about.
Smell and cover
Most foam toppers arrive vacuum-rolled and smell for a day or two after opening. Unroll it in a ventilated room before making the bed. A removable, washable cover is worth having.
The main types compared
| Type | Feel | Heat | Suits | Watch out for |
|---|---|---|---|---|
| Standard memory foam | Slow sink, close hug | Warm | Cool sleepers who like to sink in | Can feel like sleeping in a hollow |
| Gel-infused memory foam | Similar hug, slightly quicker | Less warm at first | People who want memory foam but run hot | Cooling effect varies a lot between makes |
| Convoluted (egg crate) | Soft, a little springy | Cooler, air flows through | A light, cheap refresh | Often thin and low density |
| High-density firm foam | Supportive, little sink | Moderate | Back sleepers, heavier sleepers, soft mattresses | Can feel hard at the shoulders for side sleepers |
| Layered or zoned topper | Different support under shoulders, hips and legs | Depends on materials | People who wake stiff or sore | Usually costs more than a single slab |
Firm and cooling toppers for a memory foam mattress
Plenty of people searching for a topper already own a memory foam mattress. Adding another soft memory foam layer on top tends to double the sink and the heat, which is rarely what anyone wanted.
If your memory foam mattress feels too soft, or you find yourself rolling into the middle, a firm topper gives you a stiffer surface to lie on. If the problem is heat, choose a topper with a different structure (open-cell, convoluted or a layered design) rather than more of the same dense foam.
Brands you will see in the UK
You will find memory foam toppers from Silentnight, Dormeo, Simba and Emma, along with retailers' own-label ranges. They span thin budget layers to thick layered designs, so compare depth, density and the return policy rather than the brand name alone.
Where Dosaze fits (and where it doesn't)
Dosaze sells four DreamAlign toppers. Each has three distinct layers and three targeted zones of support, is designed to keep you cool while you sleep, and is made to extend the life of the mattress underneath. They are aimed at people who wake with back pain or feel unrefreshed.
Our product descriptions don't present DreamAlign as a single slab of classic memory foam. If you specifically want that slow, deep-sinking memory foam feel, read the product page details before buying. If your priority is zoned support and staying cool, they are a closer match.
Pick by how you sleep and what you need:
- For a firm topper, including on a memory foam mattress that has become too soft, the DreamAlign Firm Mattress Topper is built for firm, balanced support to keep your spine aligned.
- If you sleep on your side, the DreamAlign Side Sleeper Mattress Topper is the one set up for that position.
- If sore spots at the hips and shoulders are what wake you, look at the DreamAlign Pressure Point Relief Mattress Topper.
- Back sleepers with a stiff lower back can choose the DreamAlign Back Relief Mattress Topper.
DreamAlign won't suit you if your mattress has a deep sag, since no topper fixes that. And if you only want a thin, inexpensive layer for a guest bed, a basic egg crate topper will do the job for less.
Whichever topper you choose, the layer over it affects heat. The Dosaze Cooling Bamboo Waterproof Mattress Protector has a bamboo cooling surface and goes over a topper to keep spills off it.
Frequently asked questions
Is a memory foam mattress topper worth buying?
It is worth it if your mattress is structurally sound but feels too hard, too soft or slightly worn on top. A topper costs much less than a new mattress and can change the feel noticeably. It is not worth it if the mattress has a visible dip or broken springs, because the topper will follow that shape.
How thick should a memory foam topper be?
Around 5 cm gives a gentle change, about 7.5 cm suits most people, and 10 cm or more makes a big difference to the feel of the bed. Thicker toppers are heavier and may need deep-pocket fitted sheets. Heavier sleepers and side sleepers often prefer the deeper end.
Do memory foam toppers make you hot?
Traditional memory foam holds body heat, so many people do find it warm. Gel-infused, open-cell and convoluted toppers let more air through, and a breathable cover or protector also helps. Check your bedding as well, since a plastic-backed protector can trap heat whatever topper is under it.
Can I put a topper on a memory foam mattress?
Yes. If the mattress feels too soft, a firm topper adds a stiffer surface, and if it sleeps hot, choose a topper with a more breathable structure. Adding another soft memory foam layer usually increases both sink and heat.
How long does a memory foam topper last?
It depends mainly on foam density and how much use it gets. Low-density toppers tend to flatten sooner, while denser foam usually keeps its shape for longer. Using a protector over the topper and airing it now and then helps it last.
