JY Most.
That’s the honest answer to what comes back out of a wool carpet after you’ve moved the furniture, and it surprises people who’ve been staring at four deep pits in the lounge floor since Saturday. Wool wants to stand up. It has been trying to stand up the entire time the sofa was sitting on it, and the moment the weight comes off it starts recovering whether you help it or not.
The exceptions are worth knowing about, because they’re the ones that don’t respond to anything and there’s a whole industry of small tricks aimed at people who don’t know which they’re looking at.
Why Does Wool Spring Back When Synthetics Stay Flat?
Wool fibre has a natural crimp in it, a kink along its length, and the fibre remembers that shape. Squash it and it holds tension, like a spring under a weight. Take the weight off, warm it, add a bit of moisture, and it goes back towards the shape it wants.
Polypropylene has no memory at all. It’s plastic. Crush it under a bookcase for three years and you’ve deformed it permanently, in the same way a milk bottle stays dented.
Nylon sits in between and is closer to wool than most people expect – it’s heat-set at the factory, and heat will often bring it back.
So the first question on any indentation job isn’t how deep it is. It’s what the carpet is made of, and that changes the entire outlook. I’ve told people with wool that their dents will be gone by the end of the month without me doing anything, and told people with a cheap synthetic in the same week that what they’re looking at is what they’ve got.
Move It and Give It a Fortnight
Before anyone spends money or starts attacking the carpet with a steam iron, move the furniture off the marks and do nothing for two weeks. Vacuum the area normally, walk on it if it’s in a walkway, and leave it.
A surprising proportion of sofa dents in wool are gone or nearly gone in that time. The ones that are still obvious after a fortnight are the ones worth working on, and you’ve lost nothing but patience.
What Does a Piano Do That a Sofa Doesn’t?
It concentrates.
An upright piano weighs somewhere around 200 to 250 kilos and it delivers all of that through four small brass castors. The contact patch under each one is smaller than a ten-pence piece. A three-seater sofa might weigh 70 kilos spread across four feet with a much wider footprint, so the pressure per square centimetre is a fraction of what the piano is doing.
Past a certain load, you stop crushing pile and start crushing everything underneath it. The underlay compresses and never fully recovers. The carpet backing itself gets pressed into a permanent dimple. At that point the pile can stand up perfectly and you’ll still see a dip, because the floor under the pile is no longer flat.
I looked at a room in Muswell Hill, N10, where an upright had stood against a chimney breast for eleven years. Four holes you could have lost a marble in. The wool came back beautifully with steam and teasing. The dimples in the underlay stayed exactly where they were.
Castor Cups, and the Little Plastic Discs That Don’t Work
The clear plastic discs sold in packs for furniture feet are fine under a dining chair and useless under anything heavy. They spread the load across two or three centimetres, which isn’t enough to matter.
What works is a proper hardwood or metal castor cup with a wide base, or a piece of plywood cut to sit under the whole instrument and covered with felt. Ugly, and it saves the floor. Under a piano I’d want something close to A4-sized under each castor if the customer can live with the look.
The other trick, which costs nothing, is moving heavy furniture two or three inches every few months so the load doesn’t sit in the same spot for a decade. Nobody does it, and the people who do have flat carpets.
How Do You Get an Indentation Out of Wool?
Moisture, heat, and then mechanical teasing, in that order, repeated more times than you’d like.
The version I use on site is steam from a distance. Steam released above the pile rather than pressed into it, enough to dampen and warm the fibre without soaking the backing. Then a stiff brush or a dinner fork worked through the tuft to lift it, then a slow pass with an upright vacuum with the beater bar engaged to stand it up, then let it dry. Two or three rounds over an afternoon beats one aggressive round.
Order matters more than equipment here. Brushing a dry crushed tuft does very little and can fray the tips. Warm it first, work it while it’s damp and pliable, stand it up while it dries, and the fibre sets in the position you left it in. Get that sequence backwards and you’ll spend an hour achieving nothing.
A clothes steamer, the upright sort people buy for curtains, is the best fifty quid a household with wool carpet can spend. Held four or five inches above the pile it does everything my kit does, slower. A kettle held at arm’s length works too, and I’ve done exactly that in a top-floor flat in Chiswick, W4, where the customer’s steamer had packed up and she wanted to watch me do it so she could manage it herself next time. Took three passes and most of a pot of tea.
Be sparing with the water either way. The aim is warm and damp, and a dent that’s soaked is a dent that dries slowly with a mark round the outside of it.
The internet’s favourite version is the ice cube. Put cubes in the dent, let them melt, blot, brush. It does work on shallow marks in wool, slowly. My view is that it’s a poor method and it’s recommended far too widely, because what you’re doing is dumping cold water into the backing with no heat and no airflow to get it out again, and in a carpet with a jute backing you can end up with a brown ring where the dent was. That trade is a bad one.
Why Steam Works, and Where It Scorches
Heat plus damp gets the fibre to relax enough to reset. That’s the same principle a hairdresser works on.
The failure comes from contact. An iron pressed onto a damp cloth over wool will glaze the tips and you can’t undo that. If you’re doing it at home, keep the iron moving, never let it touch the pile directly, use a clean white cotton cloth, and check the pile every ten seconds rather than every minute. On a synthetic, contact heat melts rather than glazes, which is worse and faster.
A customer in Clapham, SW4, did this with a travel iron on a wool berber and left a shiny oval the size of a hand. I couldn’t fix it. Nobody can.
How Do You Know It’s Crushed for Good?
Get a torch, hold it low and shine it across the dent rather than down into it.
If the fibres in the dent are standing up but the whole area sits lower than the surrounding carpet, that’s backing and underlay compression. You’ve got what you’re going to get. Old crumb-rubber underlay is the worst offender for this, and it’s under a lot of London floors laid before the mid-nineties.
If the fibres are lying over flat and pointing in one direction, that’s pile crush and it’ll respond to work. Those tufts are folded, not destroyed.
Then there’s the third thing, which gets mistaken for both. A pale or dark rectangle where furniture stood, with the pile standing perfectly normally, isn’t an indentation at all. It’s either shading from the fibres lying differently, or it’s the rest of the room having soiled and faded around a protected patch over eight years. Cleaning brings the room closer to the patch. It never brings the patch back to the room.
A Dent and a Shade Mark Are Not the Same Problem
Run your hand across the boundary with your eyes shut. A dent you can feel. A shade mark you can’t, and the edge will be sharp and geometric rather than soft.
Give it a fortnight and a dent changes. A shade mark looks identical on day one and day ninety.
Should You Pay Somebody to Do This?
No, and this is the bit my trade would rather I left out.
Indentation recovery on wool is a job for a kettle, a fork and a Saturday afternoon. It is not skilled work. Charging a call-out fee to come and steam four dents out of a lounge carpet is, in my opinion, close to taking money for nothing, and there are firms in London selling “pile restoration” as a line item at forty or fifty pounds a room on carpets that would have recovered on their own.
If I’m in the house cleaning anyway, I do the dents as part of the job and I don’t put them on the invoice. Takes ten minutes.
The one time it’s worth calling somebody is when the marks are in a wool rug rather than a fitted carpet, the rug has value, and the crushing has been there for years. Deep-set crush in a hand-knotted rug responds to proper washing and controlled drying under tension, which is workshop work and isn’t something you’ll reproduce with a fork.
Everything else – give it a fortnight, then steam and tease, then accept what’s left.
There’s a flat in Blackheath, SE3, where the piano moved out in March and the four dimples are still there in the underlay, and the owner has put a plant stand on two of them.