Sealy Ortho Plus Bronze King Size Mattress
The Sealy Ortho Plus Bronze is an extra firm sprung mattress built for people who want proper orthopaedic support rather than a soft, sink-in feel.
- Extra-firm support
- Stable edges, no roll-off feeling
- Double-sided to spread the wear
£459
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Sealy Ortho Plus Bronze Mattress
More available sizes
Mattress details
Mattress
Sealy Ortho Plus Bronze Mattress
Size
Firmness
Extra Firm
Construction
Foam
Orthopaedic
Depth (cm)
28
Layers
4
Layer Details
Knitted Cover
A soft knitted cover that's breathable, which means heat can escape rather than build up. It helps keep you at an even temperature through the night.
Soft White Fibres
Fibre fillings made from 100% polyester, chosen for recovery and durability. In practice that means the comfort layer springs back rather than flattening quickly.
PostureTech CS Springs with EdgeGuard
The PostureTech Core Support spring system responds to changes in your sleeping position, targeting support where you need it most. Each spring holds an EdgeGuard high-density foam insert, which strengthens the mattress edges and extends the springs' lifespan.
PowerPack Core
The PowerPack at the core works with the PostureTech system to keep your lumbar region comfortable and safely aligned. It's the layer doing the deep support work for your lower back.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Proper space for two on a firm surface: At 75cm each for two people sharing, you can both settle into your own position without negotiating over the middle.
- Less disturbance when your schedules differ: The PostureTech CS springs respond to movement where it happens, so an early alarm on one side is less likely to travel across the extra width.
- Extra length for taller sleepers: The UK king is 10cm longer than the UK double at 200cm, so a partner approaching six foot stops sleeping diagonally.
- Edges you can actually use: Each spring carries an EdgeGuard high-density foam insert, which means the outer 75cm you each claim stays supportive right to the side rather than sloping away.
- Double-sided wear across a bigger surface: Because it's turnable with fillings on both sides, regular flipping spreads the wear evenly, although a king is a two-person job to turn.
This size suits you if...
You share the bed every night and a double has started to feel cramped, you both want firm orthopaedic support rather than a soft sink-in feel, or one of you is tall enough that the extra 10cm of length over a UK double matters. It also suits couples on different schedules who want movement on one side to stay on that side.
Consider another size if...
You sleep alone, or your room falls short of the 2.7m x 2.9m we suggest for a UK king. The UK double would suit a smaller room, and we suggest at least 2.6m x 2.8m for that size.
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FAQ's
Is a UK king Sealy Ortho Plus Bronze big enough for a couple?
Yes, comfortably for most. It gives 75cm each for two people sharing, which is noticeably more personal space than a double. Because the surface is extra firm, you also sit on top of it rather than rolling towards each other. If you regularly share with a dog or a child as well, the UK super king adds another 30cm of width.
What room size do I need for a king size Ortho Plus Bronze?
We suggest at least 2.7m x 2.9m, which leaves enough space to walk round the bed and open drawers. That's our guidance rather than Sealy's. A new build master bedroom can shrink surprisingly once wardrobes go in, so measure the usable floor, not the room on the plan, before committing to the 150 x 200cm footprint.
Will my partner feel me get up early on this mattress?
Less than on a smaller, softer bed. The PostureTech CS springs respond to changes in position where they happen, and the extra firm surface doesn't dip broadly when weight shifts. Add the 75cm each of width in a UK king and someone leaving hours before you is a smaller event than it would be on a double.
Can two people turn the king size Ortho Plus Bronze?
Yes, and you'll want two. The mattress is double-sided with fillings on both faces, so regular turning is part of owning it, and at 150 x 200cm it's an awkward size to flip alone. Sealy doesn't publish a weight for this size, so if flipping a big mattress isn't practical for you, factor that in before buying.
Is the UK king long enough for someone over six foot?
At 200cm, the UK king gives 10cm more length than the UK double, which is often the difference between feet on the mattress and feet hanging off. For most people up to around six foot it's a comfortable fit. The UK super king is the same length, so sizing up buys width, never extra length.