Sealy Steeple Ortho Plus PostureTech Mattress reviewed

The Sealy Steeple Ortho Plus PostureTech is a 29cm, double-sided firm spring mattress sold by Mattress Man, with hand tufting on both faces and a Powerpack in the centre for lumbar support. It is a traditional orthopaedic build for back and front sleepers who are happy to turn their mattress.

Construction

The Steeple listing at Mattress Man describes a PostureTech spring unit with a Powerpack at its centre, Edge Guard (high-density foam wrapped around the springs), a soft quilted cover and buttons tufted through both sleeping surfaces. Mattress Man classes the PostureTech unit as open coil, made from one continuous length of wire. The Steeple does not appear among the models on Sealy’s own Ortho Plus page, but its feature list matches the Sealy Grasmoor, which heads that collection, point for point.

• Support: PostureTech spring unit, rated “Firmer” by Mattress Man
• Lumbar zone: Powerpack in the centre of the mattress
• Edge: Edge Guard high-density foam border
• Surface: hand tufted, double sided, 29cm deep
• Made in: the UK

Prices by size

At the time of writing (September 2026), Mattress Man sells four sizes. The super king comes only as a zip and link pair of two halves.

For context, the 18th National Bed Federation consumer survey of 1,000 recent buyers found a mean price of £543, which puts the Steeple double within a few pounds of the UK average.

Firmness and who it suits

Mattress Man grades the Steeple “Firmer”, one step below its “Extra Firm” grade, and says the grade describes support rather than comfort. We rate it 7 out of 10. That suits back and front sleepers and heavier adults. Side sleepers usually need more give at the shoulder and hip than a tufted spring surface offers.

Research does not back the idea that the firmest mattress is best for back pain. A randomised trial of 313 adults published in The Lancet (Kovacs et al., 2003) found better pain and disability scores after 90 days on medium-firm mattresses than on firm ones. Choose the Steeple because you like a firm feel, not as a treatment.

Trial, guarantee and care

Mattress Man offers a 60-night exchange trial, activated by buying a mattress protector, with exchanges between nights 30 and 60 and a £50 exchange fee; it is not a refund. Sealy adds a 5-year guarantee, handled first by the retailer. Being double sided, the Steeple needs turning: the National Bed Federation’s Bed Advice care guide suggests alternating a rotation and a flip every week for three months, then monthly. Mattress Man’s 188 customer reviews average 4.7 out of 5.