SleepSoul Space 4000 Orthopaedic King Size Mattress
The SleepSoul Space 4000 Orthopaedic Mattress is a pocket spring design with 4,000 springs, which means each spring can respond to your body independently rather than the whole surface moving as one.
- Firm feel for back & front sleepers
- CoolGel foam helps you sleep cooler
- Non-slip base stays put on frames
£635
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SleepSoul Space 4000 Orthopaedic Mattress
More available sizes
Mattress details
Mattress
SleepSoul Space 4000 Orthopaedic Mattress
Size
Firmness
Firm
Construction
Pocket Spring
Orthopaedic
Depth (cm)
Layers
6
Layer Details
Soft cover
A knitted cover, which another page describes as Tencel. It's the surface you lie on, so it gives the mattress a smooth, soft first touch.
Memory foam
A 1cm layer of memory foam. It's thin, so it adds a little cushioning under your body without taking away the firm feel.
CoolGel foam
A 3.5cm layer of CoolGel foam. It's the thickest foam layer here and adds comfort over the springs, with the gel aimed at keeping the surface from feeling too warm.
Mini pocket springs
A layer of 2000 mini pocket springs. Each one moves on its own, so the surface can follow your shape more closely under the foam.
Support pocket springs
A layer of 2000 support pocket springs that forms the core. It carries your weight and keeps you held level, which gives the mattress its firm, supportive base.
Non-slip base fabric
A non-slip underside made for bedframes and ottomans. It helps the mattress stay where you put it, so it doesn't creep around on the base.
Layer details from mattressman.co.uk and mattressonline.co.uk product pages, October 2026.
Key benefits
- More room each than a UK double: The UK king gives you 7.5cm more width each than the UK double, which means fewer elbows and a little breathing space when one of you sprawls.
- Less disturbance on split schedules: Extra width combined with springs that move independently means an early riser can slip out while the other partner has a better chance of sleeping on.
- Extra length for taller partners: At 200cm long, the UK king adds 10cm over the UK double, so anyone approaching 6ft is less likely to find their feet at the edge.
- Firm-leaning support across a wider surface: The orthopaedic positioning suggests a sturdier feel, and on a UK king there is enough space to shift position or prop up pillows without crowding your partner.
- A sensible middle ground on room size: We suggest at least 2.7m x 2.9m for the UK king, which asks less of your bedroom than the UK super king does.
This size suits you if...
You share a bed with someone whose alarm goes off hours before or after yours, one of you is tall enough that a UK double feels short at the foot, or you have simply outgrown elbowing each other for space and want firmer support without sizing all the way up.
Consider another size if...
Your bedroom is tighter than 2.7m x 2.9m once furniture is in. We'd recommend the UK double instead, for which we suggest at least 2.6m x 2.8m.
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FAQ's
Is the SleepSoul Space 4000 UK king long enough for tall people?
The UK king is 200cm long, or 6ft 6in, which is 10cm longer than the UK double. If one of you is approaching 6ft, that extra length is often the real reason to upgrade, more so than the width. The UK super king is the same length, so going larger adds width only.
Will I feel my partner move on a SleepSoul Space 4000 UK king?
Less than on a smaller size, most likely. The pocket springs respond individually, which limits how far movement travels, and the UK king gives you 75cm each against 67.5cm on the UK double. That extra gap helps when one of you gets up early or shifts around a lot through the night.
SleepSoul Space 4000 UK king or UK super king for a couple?
The UK super king gives 90cm each, so the UK king gives you 15cm less each. If you regularly share the bed with a child or a dog, the UK super king may feel calmer. It needs more floor space though: we suggest at least 3m x 2.9m, against 2.7m x 2.9m for the UK king.
Will a UK king SleepSoul Space 4000 fit in a new build bedroom?
Measure after the wardrobes go in, as new build rooms often shrink once furniture is placed. We suggest at least 2.7m x 2.9m for a UK king, with around 3.2m x 3.2m feeling comfortable if you want bedside tables and room to walk round both sides.
Is upgrading from a double to the SleepSoul Space 4000 in UK king worth it?
For most couples, yes, if the room allows. You gain 15cm of width and 10cm of length over the UK double, which you notice most during pregnancy, recovery or when one of you is tall. If your bedroom is under 2.7m x 2.9m, the UK double is the more practical choice.