Sealy Steeple Ortho Plus Single 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
Get the lowest price we've found
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
Sealy Steeple Ortho Plus Mattress
More available sizes
Mattress details
Mattress
Sealy Steeple Ortho Plus Mattress
Size
Firmness
Extra Firm
Construction
Orthopaedic
Open Coil Spring
Depth (cm)
29
Layers
2
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.
Key benefits
- Firm support in a small footprint: At 90cm wide, it delivers the zoned PostureTech lumbar support of the larger sizes without demanding a big bedroom.
- Works in a spare room that earns two uses: A single against one wall leaves room for a desk, so a guest room can stay a working office the rest of the year.
- Suits a solo adult sleeper: Extra firm is a deliberate choice, and the UK single gives one back-support-focused sleeper the full benefit without paying for unused width.
- Cheap, easy bedding: Single sheets and duvets are the most widely stocked of any size, which keeps running costs down for guest beds and student rooms.
- Check depth on raised frames: At 29cm this is a deep mattress, so measure guardrail height before pairing it with a bunk, cabin or mid sleeper frame.
This size suits you if...
You're a single adult who wants genuinely firm lumbar support and sleeps alone, your spare room needs a bed that leaves space for a desk and guests still get proper support, or you're kitting out a student room or first flat where the frame is provided and the room is tight. The 90 x 190cm footprint fits where wider sizes simply won't.
Consider another size if...
You're an adult with the room for something wider, or you tend to shift around at night and feel hemmed in at 90cm. We'd recommend the UK small double instead: it's 30cm wider, the same length, and we suggest at least 2.4m x 2.8m for it.
Similar Mattresses in This Price Range
Did you know? On Mattress Unboxed we have over 1,000 different mattresses to suit all types of sleepers. View all mattresses.
FAQ's
Is the Sealy Steeple Ortho Plus single suitable for a child's bed?
It fits the standard children's bed size at 90 x 190cm, but think carefully about the feel. This is an extra firm orthopaedic mattress, and lightweight sleepers, which most children are, may find it too hard on shoulders and hips. It's better matched to a teenager or adult who specifically needs firm back support.
Will the Sealy Steeple Ortho Plus fit a bunk or mid sleeper frame?
The width and length match standard UK single frames, so the footprint fits. The sticking point is depth: at 29cm this is a deep mattress, and many bunk beds specify a maximum depth so the guardrail stays effective. Measure from the base to the top of the guardrail before buying.
How much room does a UK single mattress need?
We suggest allowing at least 2.1m x 2.8m of floor space for a UK single, which leaves room to walk alongside the bed and open doors and drawers. That modest footprint is why the single works under a loft slope, in a box room, or in a spare room that doubles as an office.
Is a UK single big enough for an adult?
For one adult who sleeps fairly still, yes: 90cm of width is the UK standard for solo sleeping. If you're broad shouldered or move around a lot, the UK small double is 30cm wider and the same length, which gives noticeably more elbow room in a room measuring at least 2.4m x 2.8m.
Where can I compare prices for the Sealy Steeple Ortho Plus single?
Prices for this exact size vary between retailers and change often, so quoting a figure here would go stale quickly. Compare the retailers listed on this page instead: the prices shown are updated as retailers change them, so you're seeing current pricing for the UK single specifically.