Sealy PostureTech Alderney Single Mattress
The Sealy PostureTech Alderney Mattress combines twice-tempered PostureTech springs with a MemorySense foam layer, which means firm, responsive support with some pressure-relieving cushioning on top.
- Firm, supportive feel
- Pressure-relieving foam on top
- Edge-to-edge support across the bed
£399
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Sealy PostureTech Alderney Mattress
More available sizes
Mattress details
Mattress
Sealy PostureTech Alderney Mattress
Size
Firmness
Firm
Construction
Foam
Memory Foam
Depth (cm)
Layers
3
Layer Details
MemorySense foam layer
A pressure-relieving foam that Sealy says instantly cocoons your body. It gives the firm mattress some cushioning where you need it.
Responsive foam layer
An additional layer of responsive foam that Sealy says enhances comfort. It adds a little more padding to the feel of the mattress.
PostureTech Core Support springs
Twice-tempered PostureTech springs that provide responsive support. They give the mattress its firm, supportive base.
Layer details from dreams.co.uk product page, November 2026.
Key benefits
- A small footprint for busy rooms: At 3ft x 6ft 3in, the UK single leaves floor space for toy storage, a desk and a wardrobe, so a small bedroom still has a clear walkway.
- Edge support on a narrow bed: EdgeGuard edge-to-edge support means you can sleep closer to the side without rolling off, which matters more on a 90cm width than on a wider bed.
- Firm support with a cushioned top: Twice-tempered PostureTech springs give the base its firm feel, while the MemorySense layer adds some cushioning at the surface so it doesn't feel completely unyielding.
- Two beds in one guest room: A pair of UK singles lets a spare room sleep two guests who would rather not share, and you can still push them together if a couple stays.
- Fits under a sloping ceiling: In a loft conversion, the narrow UK single can sit lengthways under the slope where a wider bed would leave you bumping your head on the way in.
This size suits you if...
You sleep alone and want a firm, supportive feel, or you're furnishing a child's room, a student room or a compact spare room where floor space matters more than bed width. It also fits a guest room you'd like to set up with two separate beds.
Consider another size if...
You share the bed with a partner, or you're a solo adult who likes room to spread out. We'd recommend the UK double instead, which is 45cm wider and needs at least 2.6m x 2.8m.
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FAQ's
Will a Sealy Alderney UK single fit a cabin bed or mid sleeper?
The UK single is the standard 90 x 190cm size, so its width and length should match most cabin beds, bunk beds and mid sleepers. Raised frames usually set a maximum mattress depth so the guard rail stays effective. Check that limit against the brand's own depth guidance before you buy.
What size bedroom do I need for a UK single Sealy PostureTech Alderney?
We suggest at least 2.1m x 2.8m of floor space for a UK single. That allows you to walk around the bed and open drawers or a wardrobe. If you're putting two singles in a shared or guest room, plan for a walkway between them as well.
Is the Sealy Alderney single a good choice for a child?
It can be, as long as your child is comfortable on a firm mattress. The foam layers add some cushioning, but the rating stays firm. Lighter side sleepers, which includes many children, may find it a little unyielding at the shoulders and hips. A child who sleeps on their back or front may get on with it better.
Should one adult get the Sealy Alderney in a UK single or UK double?
The UK single suits an adult in a small room, or one who sleeps fairly still. The UK double is the same length but 45cm wider, giving you more room to turn over. It needs at least 2.6m x 2.8m, so measure first.
What bedding fits a Sealy Alderney single mattress?
Standard UK single fitted sheets suit the 90 x 190cm size, and a single duvet measuring 135 x 200cm covers it with some overhang. Single bedding is easy to find on the high street, which helps if you're buying spare sets for a child's room or two guest beds.