The Working Upholsterer’s Bible · Tools
The right foam for the job — type, density, firmness, depth and fire grade — because the wrong foam is the difference between a cushion that lasts ten years and one that’s flat by next winter.
The single thing most people get wrong: density and firmness are not the same. Density is the weight of the foam — it decides how long the cushion lasts. Firmness is how hard it feels. A cheap foam can be firm and still collapse in a year; a good foam can be soft and last a decade. Pick the job below and this gives you both, the right way round.
Fill in all three and you’ll get a foam cut size below.
Density = lifespan. It’s the weight of foam per cubic metre and the best single clue to quality. It is not firmness.
Firmness = feel. Chosen for the job and your taste, independently of density.
Hardness figures are an approximate guide in Newtons (the number after the density in UK foam codes, e.g. RX38/150). They vary by supplier and test method — treat them as a steer, and feel a sample where you can.
Read the foam construction chapter → · Materials charts · All tools