Sealy PosturePedic Denison Combination Mattress

Assessed from the specification published by crushedvelvetbedstore.co.uk, captured November 2026, and from regular price comparison across our UK retail partners.

The very firm rating gives a solid, supportive surface, which suits back sleepers and anyone who dislikes the feeling of sinking in. Eco ComfortCore foam is there for hip and lower back support, so your midsection is held up. The top layer is graphite foam that feels cool to the touch, a welcome start if you tend to run warm. The cover is endorsed by Allergy UK, and the UniCased edge support system is designed to keep the sides supportive. It's handmade in the UK, and Sealy backs it with a 7-year guarantee.

Back sleepers
The very firm rating gives a flat, solid surface, which means your body stays held up on top of the mattress rather than sinking in.

Warm sleepers
A graphite foam top layer feels cool to the touch, which gives you a more comfortable start to the night if you tend to run warm.

Allergy sufferers
The cover is endorsed by Allergy UK, so it is a sensible pick if you want a mattress with an allergy-focused cover.

Couples
UniCased edge support is designed to keep the sides supportive, and the UK double, king and super king sizes give two people room to spread out.

If you prefer sleeping on a soft or medium mattress, this might not be the best choice. It's rated very firm, so side sleepers, particularly lighter ones, may find it too unyielding at the shoulders and hips. It also can't be flipped, so you can't turn it over to refresh the surface. Sealy doesn't publish a spring count.

How firm is the Sealy PosturePedic Denison?

It's rated very firm, which gives a flat, supportive feel with little sinking in. That suits back sleepers and people who like a hard surface, although anyone who wants a softer, cushioned feel should choose a gentler mattress.

How deep is the Sealy PosturePedic Denison?

It's 28cm deep. That's a fairly substantial mattress, so check that your bed frame and any fitted sheets will suit that depth before you buy.

What sizes does the Sealy PosturePedic Denison come in?

It comes in a UK single, UK double, UK king and UK super king. A UK small double isn't offered everywhere, so check the retailer before ordering if you need that size.

Does the Sealy PosturePedic Denison come with a trial or guarantee?

Sealy gives a 7-year guarantee. Dreams also offers a 100-night comfort guarantee, which is the retailer's own offer, so check its terms before you buy.

Is the Sealy PosturePedic Denison good for side sleepers?

Probably not for most. It's rated very firm, and side sleepers usually need more give at the shoulders and hips. It suits back sleepers better, although heavier side sleepers may find it more comfortable.