Sealy Steeple Ortho Plus Double 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
£433
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Sealy Steeple Ortho Plus Mattress
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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
- A shared bed with shared support: The zoned PostureTech springs firm up the middle third, which means both of you get lumbar support rather than rolling towards a dip in the centre.
- Fits the rooms most of us have: We suggest a minimum of 2.6m x 2.8m for a UK double, which suits the majority of UK bedrooms without crowding the wardrobe.
- 67.5cm each when sharing: Two people get 67.5cm each, enough for back and combination sleepers on a firm surface where you sink in very little.
- Extra firm holds up on the smaller footprint: An extra firm build resists roll-together, so a couple on a UK double disturbs each other less than on a softer mattress this width.
- Easy to dress and to move: Double sheets and duvets are stocked everywhere, and this size copes with turning stairs and tight landings better than a UK king would.
This size suits you if...
You share the bed and want genuinely firm orthopaedic support in a size that still leaves walking room, or you sleep alone, mostly on your back, and like space to spread out. It also suits a guest room that hosts visiting couples, where a firm, no-fuss surface pleases most backs without dominating the room.
Consider another size if...
You share every night and one of you is broad shouldered or restless, because 67.5cm each can feel snug. We'd recommend the UK king instead: 15cm wider, 10cm longer, and we suggest at least 2.7m x 2.9m of room for it.
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FAQ's
Is the Sealy Steeple Ortho Plus double big enough for two adults?
For most couples, yes. You each get 67.5cm of width, and because this mattress is extra firm you stay on your own side rather than rolling into a central dip. Larger or restless pairs may prefer the UK king, which is 15cm wider and 10cm longer, though it needs a bigger room.
What room size do I need for the Sealy Steeple Ortho Plus in a UK double?
We suggest at least 2.6m x 2.8m, with around 3m x 3m the comfortable norm. The mattress itself is 135 x 190cm, so a typical UK master or a decent second bedroom will take it with bedside tables on both sides and drawer space to spare.
Will a double Sealy Steeple Ortho Plus get up narrow stairs?
At 135cm wide it's one of the easier shared sizes to manoeuvre, and it copes with the turning stairs of older terraces and tight new build landings better than a UK king. It's still a substantial firm mattress, so measure your stairwell and doorways before ordering.
Should I get this mattress in a double or a king?
Choose the UK double if your room is nearer our 2.6m x 2.8m minimum, or if it's a guest room. If you share nightly and the room allows at least 2.7m x 2.9m, the UK king adds 15cm of width and 10cm of length, which taller sleepers will notice on a firm surface.
Is the UK double Sealy Steeple Ortho Plus good for a guest room?
It's a sensible choice. A UK double fits most spare rooms alongside a wardrobe and drawers, and the extra firm feel suits occasional use, since visiting couples with bad backs tend to fare better on firm support than on something soft. Compare the retailers listed on this page for current pricing.