A dried drip of emulsion in a wool twist feels like a crumb of toast under a bare foot. You don’t see it first. You feel it, halfway down the landing at seven in the morning, and then you kneel and find eleven more.

That was a terrace off Fortis Green in Muswell Hill. Oatmeal wool twist on the stairs and landing, a hallway freshly painted in a dark sage the owner had spent a month choosing, and a decorator who had finished on the Friday, been paid, and gone to Tenerife. Most of it came out. Two spots on the top step did not, and she still knows exactly where they are.

What Happens to Emulsion as It Dries in a Wool Pile?

Emulsion is water carrying tiny particles of acrylic or vinyl polymer, plus pigment. While the water is still there, it behaves like a thin, dirty liquid and will rinse. As the water evaporates, those polymer particles are pressed together until they merge into a continuous plastic film.

Once that has happened, water can’t pull them apart again. This is the whole reason the paint stays on your wall through a decade of hands and radiators.

Touch-dry is an hour or two. The film keeps hardening for weeks after that, and a drip found a fortnight after the decorators left is a harder job than one found after two days, and a much harder job than one found while the brush was still wet. Wool makes it trickier still. The fibre has a scaly surface that paint grips, and wool drinks water, so a fresh drop doesn’t sit on the tips for long – it wicks down the yarn and dries partly inside it.

The First Day Is a Different Job

If the paint is still wet, scoop what’s standing with a spoon or a plastic card, then blot with a cloth dampened in cold water, working inwards and swapping to a clean section of cloth as often as not. Don’t rub. Rubbing a wet drip into a twist pile spreads it across three tufts where there was one.

That’s a ten-minute job, and nobody needs to ring anyone.

Where Does Decorating Paint Usually End Up on a Carpet?

The skirting line, mostly. A brush cutting in along the top of a skirting board flicks drips outwards, and the first forty centimetres of carpet takes them.

Doorways come next, because that’s where people set trays down and where rollers get reloaded. Then there’s the trodden drip – one spot stepped in and carried along as a trail of fainter footprints, usually towards wherever the kettle is.

Mist Coat Spatter Is the One People Miss

New plaster gets a mist coat, which is emulsion thinned with water so the plaster can soak it up. A roller loaded with mist coat throws a fine spray of droplets far wider than a normal coat does, and on a pale carpet the result is a haze of tiny dots within about a metre of the wall. In electric light you’ll barely see them. Open the curtains on a bright morning and the whole margin of the room looks faintly freckled. Thinned paint also soaks deeper into the yarn before it dries, which makes it harder to lift than a fat drip.

How Do We Remove Cured Emulsion From a Wool Carpet?

First, we find out where the paint sits. Parting the pile around a spot shows whether it’s a blob riding on the tips of the tufts or a stain that has run to the base of the yarn. Those are two different jobs, and the second takes three times as long.

Then a colourfastness test on a hidden area, because the softening agents that work on paint can also shift a dye that hasn’t been fixed well. Behind a door, or at the back of a wardrobe floor.

The removal itself is slow. We apply a paint and ink remover based on glycol ethers – solvents that swell and soften an acrylic film without the harsh alkalis wool can’t tolerate – in tiny amounts, with a pipette or a cotton bud, onto the paint and nowhere else. It needs a few minutes to dwell. Once the film softens, a blunt bone spatula or the back of a tamping brush breaks it into flakes, and those flakes lift out of the pile with tweezers or a crevice tool on the vacuum. As often as not the first application gets a third of it. Then we repeat, sometimes four or five times on a single spot, until nothing is left to soften.

Wool is a protein fibre and prefers slightly acidic conditions, so the area gets a mild acid rinse afterwards to take out solvent residue and bring the pH back down. We blot it almost dry and groom the pile upright by hand.

A single raised drip takes around twenty minutes. The landing in Muswell Hill had twelve, plus a trodden trail, and it took most of an afternoon.

Things we don’t use: DIY paint stripper from the hardware shop, which is formulated for wood and metal and will strip a wool fibre as happily as a door; acetone, which can damage the latex holding the tufts to the backing; and any kind of heat, which softens paint only by softening the carpet around it.

When the Paint Has Soaked Down to the Backing

A knocked-over tray is a separate problem. Paint that has run down into the base of the pile and pooled on the backing can’t be softened properly without soaking the carpet so heavily that you risk the backing and the underlay, and the solvent needs to touch the paint to work. We can lighten the surface. The base stays painted, and it shows as a darker, stiffer patch that crunches when you tread on it.

On a spill that size the realistic options are a patch or learning to live with it.

When Is Trimming the Pile Better Than Chemistry?

More often than the trade likes to admit, and this is the part I’d tell any customer before they book.

A raised drip sitting on the tips of a cut-pile twist or Saxony can often be cut out. Small curved nail scissors, the pile held upright between finger and thumb, and a snip just beneath the paint. On a carpet with a pile ten millimetres deep or more, losing two millimetres from a handful of tufts is invisible once you’ve brushed the neighbouring pile across it. You can do six drips yourself in the time it takes to find a contractor’s number, and you’ll save the call-out.

It doesn’t work everywhere. A short velvet pile or a Wilton with a clipped, even surface shows every cut, and on loop pile you’re cutting through loops that then unravel. On those, leave the scissors in the drawer.

It also doesn’t work on mist coat spatter – there are too many dots and they sit too low.

Patching a Doorway

A tray set down on a threshold usually leaves a stain a hand’s width across, right where every pair of feet in the house crosses it. Chemistry won’t get the base of that. A patch will. A good fitter cuts a matching piece from an offcut or from carpet inside a built-in wardrobe, lines up the pile direction and bonds it in, and in a doorway the join often hides under the threshold strip. On a job in Blackheath, SE3, a patch on a bedroom threshold cost the owner less than my quote for trying to clean it, so I told her to ring the fitter.

Should the Decorator Pay for Paint on the Carpet?

Yes, in my view, and I’d raise it before settling the invoice rather than after.

Protecting the floor is part of decorating. A decorator who leaves drips in a finished carpet has done the job badly, and most will come back and deal with it if asked promptly and politely. Many carry public liability insurance that covers this kind of damage, although a few spots rarely makes a claim worth anyone’s time.

Here’s the opinion that gets me into arguments with decorators. Plastic sheeting laid over carpet is lazy protection, and I’d rather see a floor covered with old bed sheets than with polythene. Paint beads on plastic instead of soaking in, so a drip stays wet, gets stepped in and walked off the edge onto the carpet. Polythene slides underfoot on a stair, too. A heavy cotton twill dust sheet absorbs the drip where it lands and stays put. Decorators like polythene because it’s cheap and they can bin it at the end of the day.

Photographs Before the Dust Sheets Come Up

Take pictures of the carpet before any work starts, and again when the sheets are lifted, with the decorator still in the room. Daylight, phone held low so the pile throws a shadow. A customer in Kingston upon Thames had both sets and got her money back for the cleaning without a single awkward phone call.

Her decorator now puts a note about floor protection on his quotes. He showed me one – it’s the line just below the VAT.