You can identify your carpet fibre with two quick tests: feel it, and burn a single shed strand. Wool feels springy and matte and, when burnt, smells like burnt hair and crumbles to ash. Synthetics melt: nylon and polyester burn to a hard bead, and polypropylene melts and is light enough to float on water. Knowing the fibre matters because it decides how the carpet must be cleaned, wool needs gentle, pH-appropriate chemistry and no heat, while synthetics are far more tolerant.
The four fibres you are likely to have
- Wool, a natural protein fibre. Springy, matte, warm to the touch, and recovers when you press it. pH-sensitive and damaged by alkaline products and heat.
- Nylon (polyamide), the most common quality synthetic. Hard-wearing and resilient, takes dye well, and tolerates cleaning well.
- Polyester, soft and luxurious to the touch, good stain resistance to water-based spills but holds oily soil. Common in plush carpets.
- Polypropylene (olefin), slick or waxy to the touch, very stain- and moisture-resistant, but flattens in traffic and holds oily soil. Common in budget and loop-pile carpets.
The feel test
Wool is springy and matte and bounces back when you press it. Polyester feels notably soft and smooth. Polypropylene feels slightly slick or waxy. Nylon sits between, resilient and slightly textured. The feel test narrows it down; the burn test confirms it.
The burn test (on a single shed fibre)
Pull a few loose fibres from an out-of-sight edge, hold them with tweezers over a sink or a non-flammable surface, and touch a flame to them:
- Wool smells of burnt hair, burns slowly, self-extinguishes, and leaves a black ash that crushes to powder.
- Nylon melts as it burns, smells faintly like celery or chemicals, and leaves a hard grey bead.
- Polyester melts with a black sooty smoke and a sweetish chemical smell, leaving a hard dark bead.
- Polypropylene melts like candle wax with a waxy smell and leaves a hard bead, and a fibre dropped in water floats, because it is less dense than water (the others sink).
Do this with a single fibre, carefully, never with the carpet itself.
Why the fibre changes the cleaning
Fibre decides the chemistry and the method. Wool is pH-sensitive: alkaline products and heat felt it, shift its dyes and degrade it, so it needs near-neutral, wool-safe cleaning and normal-temperature water, see why wool needs wool-safe cleaning. Synthetics tolerate stronger chemistry but polyester and polypropylene hold oily soil, which needs the right approach. Using the wrong method, hot water or alkaline product on wool, is how carpets get damaged in cleaning. For rugs specifically, see how to identify what type of rug you have.
Common questions
How do I know what my carpet is made of?
Feel it and burn a single shed fibre. Wool is springy and matte and burns to crushable ash smelling of burnt hair; synthetics melt to a hard bead. Polypropylene also floats on water while wool, nylon and polyester sink. The feel narrows it down and the burn test confirms it.
Is my carpet wool or synthetic?
Wool is springy, matte and warm, recovers when pressed, and burns to ash smelling of burnt hair. Synthetics feel either soft and smooth (polyester) or slick (polypropylene), and melt into a hard bead when burnt rather than turning to ash. The burn test on a single fibre is the clearest way to tell.
Why does it matter what fibre my carpet is?
Because the fibre decides how the carpet must be cleaned. Wool is pH-sensitive and damaged by alkaline products and heat, so it needs gentle, wool-safe chemistry and normal-temperature water, while synthetics tolerate stronger methods. Cleaning a carpet the wrong way for its fibre is a common cause of damage.
If you are unsure of your carpet or rug fibre, send us a photo through the contact page and we will help. See our carpet cleaning page.