Who the Westwood Core Supportive Firm suits
This is the simplest mattress on the site: one 10cm layer of high-density foam in a breathable, hypoallergenic cover, for £107 in a double and from £64 in a small single. It is also the firmest thing The Foam People make, firmer than the reflex-foam Comfort Ortho Firm, because there is no comfort layer at all between you and the base.
It exists for beds that cannot take a normal mattress. Bunk beds and cabin beds usually specify a maximum depth of around 15cm so the guard rail still does its job; most caravan bunks and some trundles are the same. For those, a firm 10cm foam mattress is the correct answer rather than a compromise, and this one is made to measure if the standard sizes do not fit. It also suits a child who has been told to sleep on a firm surface. It does not suit an adult sleeping on it every night, however firm you like your bed: for that, spend £50 more on the 20cm Comfort Ortho Firm, or read our best firm mattress picks.
Construction and materials
There is one layer. The Foam People cut a 10cm block of high-density supportive foam (the same grade they use as the base in their two-layer mattresses) and finish it with a removable-feel quilted cover that is breathable and resists dust mites. No memory foam, no reflex top sheet, no springs. That is why it is cheap, light and firm all at once, and it is why the comfort score is the lowest in the range.
Because every mattress is cut to order in their UK factory, the size list runs to 11 options including shorty (175cm) and European lengths, and they will cut other sizes on request. For a bunk with an odd internal measurement that matters more than anything else on this page.
Comfort and support
We score it 8.1 for support and 7.4 for comfort. In our testing it does exactly what a firm foam slab should: it holds flat under a light or average adult and does not hammock in the middle, which is the failing of the cheap spring mattresses that usually end up on bunk beds. Lying on your back, it keeps the hips level with the shoulders.
The comfort figure is honest about what it is not. On your side there is nothing to let the shoulder sink in, so an adult side sleeper will feel pressure within a few minutes. Children, who weigh less and are lighter at the shoulder, do not have that problem, which is why we are happy to recommend it for them and not for you. Our children's mattress guide explains why a firmer surface is the right call for younger sleepers.
Temperature
Plain high-density foam does not trap heat the way memory foam does, and with so little material there is not much to hold warmth anyway. The cover is breathable. We would call it neutral: not a cooling mattress, but not one that sleeps warm either.
Edge support and motion isolation
Edge support is better than you would expect from a budget foam mattress, because the whole thing is base-grade foam rather than a soft layer over a base. Sitting on the edge of a bunk to get a child to sleep, it does not collapse under you. Motion isolation is good, as it is on any all-foam build, though on a single that rarely matters.
Durability, trial and warranty
High-density foam with no soft layer to break down should last well beyond the 5-year warranty in a child's bed, and flipping it every few months (you can, as it is the same both sides) spreads the wear. The Foam People do not offer a home trial, so buy it for the job it is designed for rather than hoping it will do as a main bed.
Our verdict
Scored as a bunk-bed, cabin-bed or children's mattress, the Westwood Core Supportive Firm is the best value on the site: £107 for a made-to-measure, properly firm foam mattress that will outlast the bed it goes in. Scored as a mattress for an adult it is a 10cm slab, and no amount of firmness makes up for the missing depth. Buy it for the first job and the 9.2 value score is deserved; for anything else, see the rest of The Foam People range.
