Sealy Ortho Plus Grasmoor reviewed

The Sealy Ortho Plus Grasmoor is a 29cm traditional spring mattress that you turn as well as rotate, because both faces are hand tufted. Sealy places it at the top of its Ortho Plus collection, part of the Sealy Classics family rather than the Posturepedic range, so it carries the 5-year Sealy Classics guarantee. It suits people who want a firm, even surface and are happy to flip a mattress, and a double costs £499 at Trio Furnishings.

How the Grasmoor is built

The Grasmoor specification on sealy.co.uk lists five features and the same 29cm depth for every size. Sealy says the springs are twice tempered and that the Powerpack sits in the centre of the mattress, under the lower back.

Sizes and prices

Sealy makes the Grasmoor in the four standard UK sizes and sells it through independent stockists, so sealy.co.uk shows no price. At the time of writing (September 2026), Trio Furnishings in Telford, which delivers across mainland England and Wales, lists the double, king and super king, and Perfect Dreams in Colwyn Bay lists the single.

Neither stockist publishes a sleep trial on the Grasmoor, so choose it only if you already know you like a firm, tufted mattress. Perfect Dreams offers free delivery within 60 miles of its shop. Sealy allows a tolerance of plus or minus 2cm on every dimension, according to its guarantee terms, because the mattresses are made by hand.

How firm is it, and who is it for?

Sealy publishes no firmness number for the Grasmoor. Tufting on both sides, an orthopaedic spring unit and a central Powerpack put it at the firm end, which we rate 7 out of 10. Back sleepers, front sleepers and heavier adults who sink through softer tops are the natural audience. Side sleepers with sore shoulders will probably find it hard.

Firmer is not automatically better for a bad back. In a randomised trial of 313 adults published in The Lancet (Kovacs et al., 2003), people with chronic low-back pain improved more over 90 days on medium-firm mattresses than on firm ones (odds ratio 2.10 for disability, 2.36 for pain while lying in bed). A 2021 systematic review of 39 studies in the Journal of Orthopaedics and Traumatology reached the same conclusion for comfort, sleep quality and spinal alignment. If back pain is your reason for buying, treat the Grasmoor as a firm option rather than a medical one.

Turning and care

The double-sided build is the Grasmoor’s biggest practical difference from most modern mattresses. The National Bed Federation’s Bed Advice care guide recommends alternately rotating and flipping a two-sided mattress every week for the first three months, then monthly. The Sealy guarantee terms make that turning a condition of cover, rule out rolling or bending the mattress, and ask for slats about 10cm wide with gaps of no more than 7.5cm.