Written by the team that fits carpets across Isleworth, Richmond, Twickenham, Chiswick, Kew and West London every week. Short answers, no sales pitch; ask us anything we have not covered.
What underlay actually does
Underlay is the layer between the carpet and the floorboards or concrete. It gives the carpet its softness, insulates against cold and noise, protects the pile from being crushed against a hard floor, and keeps the carpet in place so it does not stretch and ripple. A good underlay under a mid-range carpet feels and lasts better than a premium carpet laid on a cheap one.
Thickness and density
Thickness is what you feel; density is what makes it last. A thick, soft underlay in a bedroom feels luxurious. The same underlay on stairs or in a hallway lets the carpet move and wear. For busy areas choose a dense, firmer grade, usually thinner. We recommend a grade per room rather than one roll for the whole house.
Room by room
Bedrooms: thick and soft, comfort first. Living rooms: medium thickness, good density, for comfort and wear. Hallways and landings: dense and firm. Stairs: the firmest, densest grade, because all the wear lands on the nosings. Rooms with underfloor heating: a low-tog underlay so the heat gets through; we will check the carpet tog rating too.
Foam, rubber, felt or crumb?
PU foam is the everyday choice: light, comfortable, good value, in several densities. Sponge rubber is heavier and very durable, good for stairs and halls. Felt and wool-felt are firm, flat and traditional, often used under wool carpets and in period houses. Crumb rubber is the hardest wearing of all and is used under heavy-traffic and contract carpets.
Can old underlay be reused?
Almost never. It will have compressed where the furniture and the footfall were, so the new carpet would wear unevenly and feel lumpy. We uplift the old underlay with the old carpet, check the floor and lay new. The exception is a recent, good-quality underlay under a carpet being replaced for colour, which we will tell you about rather than sell you a new one.
Gripper and door bars
Gripper is the spiked strip fixed around the edge of the room that the carpet is stretched onto. New gripper goes down with every fitting unless the existing strip is recent and sound. Door bars and thresholds finish the edge where the carpet meets another floor and stop the edge fraying.
Want it done?
We supply and fit carpets across West London from our base in Isleworth: samples brought to your home, measured, quoted in writing and fitted by the same team. See the carpet fitting page, stair runners, or send photos by WhatsApp for a quick opinion.
From recent jobs
Questions
Do I need underlay with a felt-backed carpet?
Felt-backed carpets can be laid without separate underlay, but they still feel and last better on one, and it is standard for stairs.
Does underlay help with noise?
Yes. A good underlay noticeably reduces footfall noise into the room below, which matters in flats and in houses with wooden floors.
What about underfloor heating?
Choose a low-tog underlay and a carpet with a combined tog rating that lets the heat through; we check both before supplying.