Sealy Steeple Ortho Plus Mattress
The Sealy Steeple Ortho Plus is an extra firm orthopaedic mattress, which means it's built for people who want a solid, supportive surface rather than a soft sink-in feel.
- Genuinely extra-firm feel
- Zoned support keeps lower back level
- Soft fibre top adds cosiness
£343
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At 29cm deep, the Sealy Steeple Ortho Plus pairs a fibre comfort layer with PostureTech Core Support Springs zoned for lumbar support. It comes in five sizes from UK Single to Super King. It's handcrafted in the UK by a National Bed Federation approved brand, and comes with a 5-year manufacturer guarantee. If you buy from Mattress Online, they list a 100-night trial. A good fit if your back needs firm support, though lightweight side sleepers may find it too hard.
Mattress specifications
Firmness
Extra Firm
Type
Orthopaedic
Depth (cm)
29
Number of Layers
2
Trial Period (nights)
100
Warranty (years)
5
Price Range
£343 to £597
Best Sleeping Position(s)
Stomach Sleeping
Certifications
BS 7177
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
Why should you choose this mattress?
The main reason to choose this mattress is genuinely firm support at a sensible price. The PostureTech Core Support Springs use zoned PowerPack technology, which means the middle third of the mattress is reinforced where your lower back needs it most. Above that, Soft White Fibres take a little of the edge off without softening the overall feel, and a Damask cover finishes it. Extra firm is a specific need rather than a safe default, so be sure it suits how you sleep before buying. If it does, the 5-year guarantee and the starting price make this a straightforward, good-value option. Owner feedback suggests it does exactly what it promises.
Key features & layer details
Comfort Layer
Soft White Fibres sit at the surface to add a touch of cosiness. They soften the first impression slightly, but this remains an extra firm mattress underneath.
Support System
PostureTech Core Support Springs with zoned PowerPack technology do the real work here. The zoning firms up support through the lumbar region, which means your lower back stays level rather than dipping.
Layer details from mattressonline.co.uk product page, September 2026.
Best suited for?
Back sleepers
Zoned PowerPack springs reinforce the middle third of the mattress, which means your lower back stays level rather than dipping when you lie face up.
Heavier sleepers
An extra firm feel over PostureTech Core Support Springs gives a sturdy, level surface, which means you sit on top of the mattress rather than sinking in.
Budget buyers
The copy calls it a good-value option, pairing genuinely firm support with a 5-year guarantee, so you get a dependable spring mattress without paying for extras.
This isn't the mattress for anyone who likes a soft, cushioned feel. Lightweight sleepers and dedicated side sleepers are likely to find it too hard on the shoulders and hips. If you want deep memory foam contouring, the fibre-and-spring build here won't give you that.
Save on an earlier or ex-display model
Some retailers still sell the earlier version of this mattress, or ex-display and returned stock at a lower price. These are the sizes where it costs less than the current model's best price.
Sealy Steeple Ortho Plus Mattress
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FAQ's
How firm is the Sealy Steeple Ortho Plus?
It's rated extra firm, the hardest end of the scale. That suits back and front sleepers who want plenty of support, and people who find most mattresses too soft. Lightweight side sleepers will probably find it uncomfortable.
Does the Sealy Steeple Ortho Plus come with a trial?
Mattress Online lists a 100-night trial with this mattress. That trial is the retailer's own offer, so check the terms wherever you buy, as they may differ between shops.
What guarantee does the Sealy Steeple Ortho Plus have?
It comes with a 5-year manufacturer guarantee. That covers you against manufacturing faults, though as with any guarantee you'll want to keep your proof of purchase.
How deep is the Sealy Steeple Ortho Plus mattress?
It's 29cm deep. Worth checking your fitted sheets fit a mattress of that depth, as some standard sheets are cut for shallower designs.
What sizes does the Sealy Steeple Ortho Plus come in?
Five UK sizes: Single, Small Double, Double, King and Super King.
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