Firmness
Extra Firm
Type
Orthopaedic
Depth (cm)
29
Number of Layers
2
Trial Period (nights)
100
Warranty (years)
5
Price Range
£357 to £657
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
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 from-£357 starting price make this a straightforward, honest option. Owner feedback suggests it does exactly what it promises.
Key Features & what's inside
- 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.
Who's it NOT for?
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.
Sealy Steeple Ortho Plus Mattress
Across 1,368 reviews on the mattressonline.co.uk product page, it holds a 4.7 rating, with owners reporting a firm, supportive feel that has eased back pain and solid construction. Some mention a grainy texture and a small number report spring issues.
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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. Prices range from £357 to £657 depending on the size you choose.
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