Sealy Steeple Ortho Plus Mattress
Mattress
Sealy Steeple Ortho Plus Mattress
Size
Firmness
Extra Firm
Construction
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.
- Space to spread out alone: At 120cm wide, the UK small double is 30cm wider than a UK single, which means a solo sleeper can change position freely on this firm surface.
- Fits rooms a double cannot: It's 15cm narrower than a UK double, so box rooms, studio flats and loft conversions keep walking space beside the bed.
- Firm support for one: The zoned PostureTech Core Support Springs reinforce the lumbar region, and a solo sleeper gets that support across the full width rather than sharing it.
- Works for occasional couples: Two adults can share for the odd night, and the extra firm build means neither sleeper rolls towards the middle when they do.
- Easy bedding and frames: 4ft is a standard UK size, so small double fitted sheets and frames are simple to find, with a standard double duvet on top.
This size suits you if...
You sleep alone, want genuinely firm orthopaedic support, and have outgrown a UK single without gaining a bigger room. Or you're furnishing a guest room or holiday let where couples stay occasionally rather than nightly, and the extra firm feel suits short visits. It also fits a teenager who needs firm back support and more width, in a bedroom that can't spare the floor space a UK double demands.
Consider another size if...
You share the bed every night, in which case 120cm is a little tight for two on a firm surface. We'd recommend the UK double instead, allowing at least 2.6m x 2.8m of room.
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Is a small double big enough for two people on a firm mattress?
For occasional nights, yes. At 120cm wide, two adults will feel close together, and because the Steeple Ortho Plus is extra firm you won't sink towards each other, which helps. For nightly sharing we'd suggest the UK double, which is 15cm wider and the same length.
What room size do I need for the Sealy Steeple Ortho Plus small double?
We suggest at least 2.4m x 2.8m. That leaves enough space to walk round the bed and open the door. If your room is smaller than that, the UK single is 30cm narrower and the same length, and we suggest at least 2.1m x 2.8m for it.
Is the small double a good size for a solo sleeper with back pain?
It's a sensible pairing. The zoned springs firm up support through the lumbar region, and at 120cm wide you get that support with room to shift position through the night. If you're a lightweight side sleeper, though, the extra firm feel may press on shoulders and hips regardless of size.
Where can I buy the Sealy Steeple Ortho Plus in a UK small double?
Compare the retailers listed on this page. The prices shown here are updated as retailers change them, so it's worth checking back before you buy rather than relying on a figure you saw last week.
Should I size up to the UK double instead?
Only if the room allows it. The UK double is 15cm wider and the same length, better for nightly couples, but it needs a room of at least 2.6m x 2.8m. If you sleep alone, the UK small double gives you plenty of width and keeps more floor clear.