Sealy PosturePedic Gladesville Combination Super King Mattress
The Sealy PosturePedic Gladesville Combination Mattress pairs a plush EternityFibre comfort layer with an extra-firm feel, which means you get a very supportive bed with a slightly softer surface on top.
- Extra-firm feel for firm-bed sleepers
- Plush fibre layer softens the surface
- Allergy UK endorsed cover
£1,999
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Sealy PosturePedic Gladesville Combination Mattress
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Mattress details
Mattress
Sealy PosturePedic Gladesville Combination Mattress
Size
Firmness
Extra Firm
Construction
Eco-Friendly
Foam
Depth (cm)
27
Layers
3
Layer Details
EternityFibre
A plush fibre comfort layer that Sealy says adds cushioning and a softer surface. It gives the top of this extra-firm mattress a little more comfort.
INFUSE Eco ComfortCore
A plant-based foam that forms part of the mattress. Sealy doesn't state where it sits in the build, but it adds a plant-based material to the construction.
AlignSupport coils
Patented coils that form the base of the mattress. They provide the firm, supportive feel this mattress is rated for.
Layer details from dreams.co.uk product page, November 2026.
Key benefits
- 90cm of your own: Two people sharing get 90cm each, which means a restless partner can turn over without you feeling crowded towards the edge.
- Space when the bed fills up: When a child wanders in during the night or a large dog settles at your feet, the 180cm width means the adults still keep a reasonable share.
- A clear step up from a UK king: Each sleeper gains 15cm compared with the 75cm each a UK king allows, which is enough to notice on every single night.
- No change in length: The UK super king is the same length as the UK king, so you gain width without changing how the bed sits against the headboard wall.
- In proportion with a big room: In a period house or a large master bedroom, a 180cm wide extra firm bed looks settled in the space, where a UK king can look slightly undersized.
This size suits you if...
You share with a partner who tosses and turns, or with children and dogs who join you overnight as a matter of routine, and your bedroom comfortably clears our suggested minimum of 3m x 2.9m.
Consider another size if...
Your room falls short of 3m x 2.9m, or the slope of a loft conversion leaves no wall long enough for 180cm of width. We'd recommend the UK king instead, for which we suggest at least 2.7m x 2.9m.
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FAQ's
Is the Sealy Gladesville UK super king big enough for two adults and a child?
For occasional visits, yes. Two adults get 90cm each on a UK super king, so a small child tucked in the middle is far less of a squeeze than on a UK king. If a child sleeps with you every night, you'll still feel the space shrink, but you're on the widest size the Gladesville comes in.
What size bedroom do I need for a UK super king Gladesville mattress?
We suggest at least 3m x 2.9m, with something closer to 3.5m x 3.2m feeling comfortable once you add bedside tables and walking space. In a loft conversion, check that the wall the bed will sit against has full headroom along its 180cm width before committing.
Gladesville super king vs king: how much extra space do you get?
The UK super king is 30cm wider than the UK king and the same length. For two people, that works out at 90cm each rather than 75cm each, so 15cm more per person. Firmness and construction don't change between the two, so you're choosing purely on space and room size.
Will a UK super king mattress fit up my stairs and through the bedroom door?
Measure before you order. Check the narrowest landing turn and whether the bedroom door swings back far enough to get 180cm of width through at an angle. Once you're confident the route works, compare the retailers listed on this page for the Gladesville in this size.
What bedding fits a Sealy Gladesville super king?
You'll need super king sheets, and a 260 x 220cm duvet suits the 180cm width so neither sleeper ends up short of cover. The mattress is 27cm deep, so choose fitted sheets with pockets deep enough to tuck under comfortably. Super king bedding costs more than king, so budget for it.