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Nobody sleeps well sneezing. I do a fair bit of allergy work in the mansion blocks around Bloomsbury — the big old flats off Marchmont Street, all high ceilings and curtains that haven’t come down in twenty years — and the bedroom is where it bites hardest. You spend a third of your life in there with your face pressed into the one object in the flat that’s a mite farm.

The better news is that a bedroom is a small room, and you can get the allergen load right down without much kit. Most of the problem is the invisible stuff — the fine dust and mite waste you never see until it’s in your lungs at three in the morning.

This is what I strip out, and the order I do it in.

Where does the dust in a Central London bedroom come from?

Two sources, roughly. Outside and inside.

Central London hands you the outside half for free. Live on a busy road — Southampton Row, Euston Road, anywhere the buses queue — and you get a steady drift of traffic dust and diesel soot through every gap in an old sash window. It settles on the sill and the top of the wardrobe, and every time you cross the room you kick it back into the air.

Inside is worse, and it’s mostly you. Human skin sheds constantly, and that shed skin is what dust mites eat. Add hair and clothing fibres, plus the fine grit tramped in on shoes and paws, and the average bedroom generates its own dust supply without any help from the street.

Then the room recirculates it. Radiators are the culprit people miss — dust settles behind them, the heating comes on, and the convection current lifts a plume of fine particles straight up into the air you breathe lying down. Warm room, still air, and a carpet holding months of it: that’s the recipe for a bad night.

What’s living in the mattress?

Dust mites, in their millions. Dermatophagoides — too small to see, and the trouble is the protein in their droppings, which goes airborne the moment you disturb the bed. A used mattress can hold a startling population; they thrive in the warm, humid environment six inches under you every night, and pillows fill up the same way.

This is the invisible stuff at its worst. You will never see a mite, and you’re breathing their waste eight hours a night.

Which surfaces cause the most trouble in a bedroom?

Soft and deep — that’s the order of trouble.

Carpet is the biggest reservoir in most bedrooms. It holds skin, mite waste, pollen and street dust down in the pile where a domestic vacuum can’t reach, and it releases the lot every time someone walks across it. Curtains come next — heavy lined curtains are dust sponges, and the ones in these Bloomsbury flats often can’t even go in a machine. Upholstered headboards and the pile of cushions nobody sits on are reservoirs too.

The case for pulling up the carpet

I’ll say the thing most people don’t want to hear. If someone in that bedroom has a real dust allergy, the carpet should come up. All of it. A sealed hard floor — engineered wood or sanded boards — gives the allergens nowhere to hide and lets a damp mop take them out of the room for good, which a vacuum on carpet never manages.

People resist it. Carpet’s warm and it’s already there, and lifting it in a rented mansion flat means a conversation with a freeholder. I understand all that. It doesn’t change the fact that a carpeted bedroom and a serious dust allergy don’t belong in the same room. If the carpet truly can’t go, a low-pile rug you can lift and beat outside beats fitted carpet you can’t. That’s the disagreeable bit, and I’ll stand by it.

How do you deep-clean a bedroom down to the allergens?

This is the main event. Work in order, top to bottom, so you’re not re-dirtying surfaces you’ve already done.

Strip the bed completely first and get everything washable into a 60-degree wash — sheets, pillowcases, mattress protector, the lot. While that’s going, start the room from the top down.

Damp-dust everything. Dry dusting is worse than useless for allergies; a dry cloth or a feather duster lifts the fine particles and throws them back into the air, where they hang for hours and settle again once you’ve left. A barely-damp microfibre traps the dust and carries it out of the room. Wipe the picture rails, the tops of doors and wardrobes, the light fittings, the skirting — anywhere a grey line has built up.

Then the mattress. Vacuum the whole surface and the sides with a HEPA machine, slowly — the allergen is heavy and clings, so you go slow and let the suction do the work. Flip it, do the other side. If you’ve never done this, the first pass off a neglected mattress fills the canister with grey powder, and that grey powder is the invisible stuff you’ve been sleeping in.

Now the floor. On a hard floor, vacuum and then damp-mop — the mop is what lifts the fine allergen out of the room rather than stirring it around. On carpet, all you can do is vacuum thoroughly with a HEPA machine and accept you’re managing it, not solving it. Do the edges and under the bed, where the heaviest reservoir sits, and pull the bed out to reach it rather than running the nozzle along the visible strip and calling it done.

Curtains come down and go in the wash if they’ll take it, or off to be cleaned. Blinds get wiped slat by slat. Finish with the soft furnishings — cushion covers off and washed, soft toys through a hot wash or a spell in the freezer if they can’t take the heat, which kills the mites just as well.

Don’t forget inside the wardrobe. Clothes shed fibres and hold dust, and a wardrobe that stays shut all week becomes a still, warm pocket where fine dust settles on the top shelf and the shoulders of everything hanging. Wipe the shelves down, and if the sufferer is bad in the mornings, that’s often the culprit — getting dressed stirs a season of dust straight into their face.

Why does washing at 60 degrees matter?

Temperature kills mites; agitation and detergent only move them around. A warm 40-degree wash leaves plenty alive to crawl back into clean bedding within days. Sixty degrees kills them outright and breaks down the allergen protein so it rinses away. Bedding wants doing weekly at that heat — not fortnightly, weekly — because the population rebuilds fast in a warm bed.

Anything that can’t take 60, some duvets and delicate covers, can go in the freezer overnight in a bag or through a tumble dryer on high heat. Both get there another way.

Do air purifiers and anti-allergy gadgets earn their keep?

Some do. Most are oversold.

A HEPA air purifier pulls fine airborne particles out of the air — pollen, some pet dander, the traffic soot drifting in off the road — and in a small central-London bedroom on a filthy main road that’s worth having. Run it with the windows shut and it keeps the ambient dust down.

This is the part people argue with me about. For dust-mite allergy in particular, a purifier does less than the box promises, because mite allergen is heavy — it settles out of the air within minutes and lives in the mattress and carpet, not floating around waiting to be filtered. Spend £300 on a purifier while sleeping on an uncovered mattress and you’ve bought a gadget, not a fix. A £25 allergen-proof mattress encasement does more for a mite allergy than any purifier on the market.

The anti-allergy sprays and acaricide powders you sprinkle on the carpet? I don’t rate them. The evidence they do much is thin, and they’re no replacement for physically removing the reservoir. Put the money towards a proper mattress cover and a HEPA vacuum.

What should you look for in a filter?

The words that matter are “true HEPA” and “sealed system”. A true-HEPA filter captures the particle sizes that carry allergens; a sealed body forces the air through the filter instead of letting it leak around the edges. Plenty of cheap vacuums pair a HEPA filter with a leaky casing, so the fine dust goes in one gap and straight out another, and you’re redistributing it with a motor. Same warning for purifiers — check the filter grade, because cheap “HEPA-type” is marketing.

How do you keep a bedroom dust-proof once it’s clean?

A deep clean buys you a fortnight if you stop there. The load rebuilds, so the room needs a light routine to hold it.

Keep the humidity down. Mites need moisture from the air to survive, and below about half humidity they struggle. A hygrometer costs a few pounds; if the room reads damp, ventilate it and get the number down, because dry air is hostile to mites in a way no spray is. This matters more in the sealed inner rooms of a mansion flat, where there’s no through-draught and the air just sits.

What does a realistic weekly routine look like?

Nothing heroic, or you won’t keep it up. Damp-dust the main surfaces once a week and vacuum the floor with the HEPA machine. Wash the bedding weekly at 60. Keep clutter off the floor and the surfaces, because every object is one more thing collecting dust you then have to clean. Take shoes off at the bedroom door, and keep the door itself shut through the day so the dust from the rest of the flat doesn’t drift in and settle.

The window is its own decision in Central London. Open it and you let the road in; keep it shut and the air goes stale and the humidity climbs. The quietest, cleanest air on a Bloomsbury street is early morning, before the traffic builds. That’s when the window comes open.

Mould on a bathroom ceiling is the job people apologise for before I’ve got my coat off. They shouldn’t. In a converted flat off Salusbury Road in Queen’s Park — one sash painted shut, an extractor that gave up years ago — black spotting across the ceiling is close to inevitable. It’s physics, not neglect.

I get called to these constantly. Top-floor conversions and basement flats. The little internal bathrooms with no window at all that developers love to carve out of a box room. Same story every time. Somebody wipes the ceiling, it looks clean for a fortnight, the black comes back darker.

This is how I shift it properly. The harder part is stopping it coming back.

Why does mould keep coming back on a bathroom ceiling in a badly ventilated flat?

Warm wet air rises. You run a hot shower, the room fills with steam, and that steam goes straight up and hits the coldest surface in the room — the ceiling, especially the bit nearest an outside wall or under a cold roof void. It condenses there into a film of water. Do that twice a day, every day, with nowhere for the moist air to escape, and you’ve grown mould whether you like it or not. The spores are already in the air. All they need is damp and something to feed on, and emulsion paint feeds them nicely.

Warm air, a cold ceiling, and nowhere for the wet to escape — that’s the whole recipe.

The ventilation is the game. A working extractor pulls the wet air out before it can settle. In half the flats I visit the fan spins but moves nothing — the ducting’s blocked, or it vents into the loft instead of outside. The corners and the wall above the shower go first, because they stay coldest and wettest. That’s where you’ll see it start, a fine grey speckling before it turns to proper black blotches. Same story in every damp bathroom I walk into.

What’s the difference between mould and a bit of surface mildew?

Worth knowing before you scrub. Mildew is the flat, grey-to-white powdery film — surface-level and slow to return, wipes off with a cloth. Mould is the raised black or dark-green spotting that’s got its roots into the paint film and sometimes the plaster behind. On a long-neglected ceiling it can go deep enough that cleaning the surface only buys you weeks.

If you wipe it and a brown or black shadow stays in the paint after it’s dry, the growth is into the substrate, and no amount of scrubbing brings that back. That ceiling needs stripping and repainting, not cleaning.

Is it safe to clean it yourself, and when should you stop?

For a patch the size of a dinner plate, on a sound ceiling, in a flat with a window you can open — clean it yourself and don’t lose sleep. Open the window wide and wear a mask, and you’ll be fine.

There’s a point where I’d stop, though, and tell a client to get someone else in. If the affected area is bigger than about a square metre, or if anyone in the flat has asthma or a chest condition, disturbing that much mould pushes a lot of spores into the air of a small room. That’s when it stops being a wipe-down and becomes a job for someone with proper extraction and containment. I say so, even when it means turning work away.

The problem with reaching for bleach

Everyone reaches for bleach. I’d rather they didn’t. Household bleach on a ceiling does one thing well — it takes the colour out of the mould, so the black vanishes and the ceiling photographs beautifully for the letting agent. Underneath, the growth is often still alive, and within a month it’s back through the paint. Estate agents love bleach for exactly this reason. It looks solved.

Bleach is also mostly water, and you’re adding more moisture to a ceiling that already has a moisture problem. On a painted surface it beads and runs and never reaches the paint film where the roots sit. A proper fungicidal wash — the kind sold for this exact job — kills the growth and leaves a residue that slows regrowth, and it doesn’t dump a pint of water on the plaster doing it. I use bleach for almost nothing on ceilings now.

How do you get mould off a painted bathroom ceiling properly?

Ventilate first. Open every window in the flat and shut the bathroom door, so you’re not seeding spores through the rest of the place. Put a mask on — a proper FFP2, not a dust hankie. Mould you disturb goes airborne, and you don’t want a lungful of it in a room that size.

Don’t dry-brush it. Scrubbing dry mould is the single worst thing you can do, because it flings spores everywhere and seeds the rest of the ceiling. Wet it down first. Mist the area with your fungicidal wash — or a dilute solution if you’re working from a concentrate — and let it sit. Ten minutes, longer on stubborn black. The point is to kill and soften the growth so it lifts rather than dusts off.

Then wipe, don’t scrub. A damp cloth or a soft sponge, one direction, folding to a clean face as you go and binning the cloth after — don’t wring a mould-loaded cloth back into your bucket and paint it around the room. Work in small sections. The black should lift onto the cloth. Where it’s ground in, a second application and a longer soak beats elbow grease every time.

Once it’s off, wash the area again with clean fungicidal solution and leave it to dry without rinsing — that residue is what holds the next lot back. Get some air moving. If there’s any working ventilation at all, run it for a few hours after.

One thing people skip: the sealant where the wall meets the ceiling, and the top run of tiles. Mould loves silicone sealant and it’ll sit in there and reinfect the ceiling from below. If the sealant’s gone black through, cleaning won’t save it — it wants cutting out and replacing.

Dealing with a textured or Artex ceiling

The rough ones are a trap. A lot of these conversions have a swirled or stippled ceiling, and pre-2000 Artex can contain asbestos. You don’t sand it and you don’t scrape it. Nothing abrasive, full stop. If the ceiling’s textured and you don’t know its age, treat it as though it does contain asbestos — gentle wet wiping only, and if the mould’s grown into the texture rather than sitting on top, get it tested before anyone goes near it with a tool.

How do you stop it coming straight back?

Cleaning is the easy half. If the flat still fills with steam twice a day and the wet air has nowhere to go, you’ll be back up that ladder by spring. I’ve re-cleaned the same ceiling for the same tenant three times in a year before we worked out the fan was wired to the light in the hall and never once came on. The extractor is the first thing to sort. After that it’s habits, and if it’s still coming, the building itself.

Run the fan every time and leave it running. Most bathroom extractors have an overrun timer; if yours doesn’t, leave it on fifteen minutes after you’ve finished. Open the window while you shower if you’ve got one that opens. Squeegee the tiles and wipe the worst of the water off afterwards — less standing water means less to evaporate back into the room.

Keep the bathroom door shut during and after a shower, so the steam doesn’t roll into colder rooms and condense on their walls instead. If you dry washing on a radiator in a small flat, that water goes somewhere too. Usually the bathroom ceiling.

The extractor fan nobody ever cleans

Pop the cover off your extractor and look at it. In most flats I visit it’s furred with a grey felt of dust that’s choking the airflow to nothing — the motor runs and the blades turn, but barely any air moves. Even a healthy fan can’t cope like that. The cover usually unclips; wash it in warm soapy water and brush the dust off the blades gently. Then check the flap on the outside wall isn’t painted shut or bunged with an old nest. That five-minute job restores more ventilation than most of what people spend money on.

If the fan vents into the loft rather than through the wall — and a shocking number do — you’re pumping wet air into the roof space and it comes straight back through the ceiling. Furred cover, ducting to nowhere. Same story in half the conversions round Kilburn. That one’s for a builder, not a cloth.

When is it not a cleaning job at all?

Sometimes the mould is a symptom of something a cleaner can’t touch, and pretending otherwise wastes the client’s money. If the same patch keeps returning in exactly the same spot within weeks of a proper clean, the problem’s in the building, and no product I own will hold it back for long.

The split that matters is condensation versus a leak, and they need different people.

Condensation or a genuine leak?

Condensation mould spreads over a broad area — the whole ceiling and the wall over the shower — following wherever the warm wet air settles. It’s diffuse and it tracks the cold spots. A leak looks different. A defined patch, often browner or ringed with a tide-mark, sometimes soft or sagging, sitting in one specific place that doesn’t match where the steam goes. A patch right under a flat roof or a soil pipe that’s wet to the touch when nobody’s showered is a leak, and it wants a roofer or a plumber before anyone bothers cleaning it.

I’ll tell a client which of the two I think it is, then get out of the way of the right trade. Cleaning a leak is painting over a warning light.

Sash windows tell you whether a terrace has been looked after or left to sulk. Stand on Tredegar Square in Bow and you can read the street off the glazing bars alone — the houses that see a decorator every few years, and the ones running the same cracked gloss they’ve had since the eighties.

I clean a lot of them. Georgian six-over-six and Victorian two-over-two. The occasional horned sash a previous owner dropped in during some ill-advised refurb. They all collect London the same way. Soot, brake dust, pollen off the plane trees, and the greasy film that lands on anything within fifty feet of a bus route. The frames cop the worst of it, because the glazing bars hold muck in every corner and nobody thinks to wipe them.

What follows is how I do the frames and bars without stripping paint or drowning the sash pockets. Slower than the glass. Worth every minute.

Why do sash windows in a London terrace get so filthy in the first place?

Position, mostly. A terrace sits flush to the pavement, so the lower sashes are a metre from passing traffic and take a constant dusting of whatever the road throws up. On Roman Road, that’s diesel and brake particulate from the 8 and the 388 grinding past all day. The upper sashes get less traffic but more weather — driving rain that carries rooftop grime down the face of the building and parks it on the meeting rail.

Then there’s the box itself. A traditional sash runs in a hollow frame with weights and cords, and that cavity breathes. Air moves through the gaps around the sashes, and it drags dust in with it. The corners of the glazing bars — the little rebate where the timber meets the glass — act like a gutter. Muck washes down, catches on the putty line, and bakes there.

Single glazing makes it worse. Cold glass sweats in a heated room, condensation pools on the bottom rail, and that damp film glues the dust down into a paste. That paste is the tell. If you run a finger along a bottom rail and it comes away with a grey smear rather than dry dust, the window’s been sweating and nobody’s touched it in a while.

What’s the black grime actually made of?

People assume it’s soot, and part of it is. The rest is iron. Brake dust is mostly iron oxide and it’s magnetic and it stains — which is why the black bloom on a windowsill near a junction goes slightly rust-brown when it’s wet. Add pollen in May and the oily haze that comes off warm tarmac in July. The neighbours still burning smokeless throw in a bit of chimney carbon. Together you’ve got a coating that plain water shifts about ten per cent of.

The iron content is why I don’t bother with a quick wipe on these. It smears. You need to lift it, not spread it.

What kit do you actually need, and what can you leave in the van?

Less than you’d think. Two buckets — one wash, one rinse, because if you rinse from the same bucket you’re painting grime back on. A handful of microfibre cloths, the flat-weave kind, not the fluffy ones that shed and catch on old timber splinters. A soft detailing brush, the sort you’d use on a car dashboard, for the corners. Wooden cocktail sticks. A pot of neutral pH cleaner — I use a dilute sugar-soap substitute at about half the strength the tub tells you, because full strength on old gloss will dull it.

That’s the list. Everything else is showing off.

The case against a pressure washer here

Someone always suggests it. Don’t. A pressure washer on a sixty-year-old sash will drive water straight past the putty and into the box, where it sits against the cords and the weights and starts them rotting from the inside. I’ve pulled sashes apart in Bow where the cord snapped six months after a well-meaning window firm blasted the frames — the water never left the box, the timber went soft, and the whole balance failed.

The water-fed pole brigade have a lot to answer for on period terraces. Deionised water and a stiff brush is fine on uPVC and fine on the glass. On painted Victorian timber it’s clumsy — too much water, no control in the corners, and it leaves the glazing bars streaked because the brush can’t get into the rebate. I’ll take a bucket and a cloth over a pole on a heritage frame every time, and I’ll argue it with anyone.

How do you clean the frames and glazing bars without wrecking the paint?

Start dry. Before any water touches the frame, take the soft brush and work all the loose grime out of the corners and off the bars — top rail, meeting rails, the vertical stiles, then the bottom. Loose dust plus water makes mud, and mud in the corners is a nightmare to shift, so get it dry first. Brush it downward and let it fall onto a dust sheet on the sill.

Now the wash. Wring the cloth out properly — damp, not dripping. You want enough moisture to lift the grime and not a drop more running toward the putty line. Work top to bottom, one section at a time, folding the cloth to a clean face every couple of passes. The moment a cloth face looks grey, turn it. A dirty cloth on old gloss is sandpaper.

The glazing bars are the slow bit. Each bar has two faces meeting the glass at a shallow angle, and that angle is where the paste sits. Wrap the cloth over a fingertip, press it into the rebate, and draw it along the whole length of the bar in one stroke. One stroke, then reposition — don’t scrub back and forth, because scrubbing worries at any hairline crack in the paint and lifts it. On a six-over-six you’ve got a lot of bars and it’s tedious. There’s no shortcut I’ve found in fifteen years, and I’ve looked.

Rinse each section with the second cloth and clean water, same top-to-bottom order, same damp-not-dripping discipline. Then dry it. A dry microfibre over the timber and the bars stops water spotting and stops any residual moisture creeping toward the box. That’s the tell of a rushed job — water spots dried onto the paint and a faint tide-line along the bottom rail where someone left it wet.

Dealing with flaking paint on a pre-1970s sash

This is where you stop and think. Any painted timber from before about 1970 may have lead in the older layers, and a flaking sash on a Victorian terrace almost certainly does under the newer coats. You do not brush hard at flaking lead paint, you do not sand it, and you do not create dust. If the paint is stable — no loose flakes, no chalky powder coming off on the cloth — clean it gently and leave it. If it’s actively shedding, that’s a decorator’s job with the right controls, not a cleaning job, and I tell the client so.

I’ll wipe a flaking frame with a barely-damp cloth to knock the surface grime back, working slowly so nothing goes airborne, then bag the cloth rather than shaking it out. Overcautious, maybe. It’s lead. I’d rather be dull about it.

How do you get into the corners of the glazing bars?

The corners are where every rushed job shows. Where the glazing bar meets the frame you get a tight junction that a cloth-covered finger can’t quite reach, and that’s where a black triangle of grime survives even after the rest looks spotless. A black triangle in the corner is the tell every time.

This is what the cocktail sticks are for. Wrap a corner of a damp microfibre round the blunt end of a wooden stick — never a metal tool, which scratches glass and gouges soft old paint — and use it to push into the junction and drag the grime out. Slow, fiddly, and it’s the difference between a frame that looks clean from the pavement and one that looks clean from eighteen inches, which is where the client stands.

Warm soapy water sits on stubborn spots better than a cold wipe. For a baked-on deposit that won’t budge — south-facing bottom rail, full sun, years of neglect — lay a warm damp cloth over it for a minute or two and let it soften before you touch it. Patience does more than pressure on old timber. That’s a rule I’d carve over the door.

What about the putty line?

The putty is fragile and you treat it as such. Old linseed putty goes hard and brittle and it’ll crack if you lean on it, so clean along the line, not into it, with a light touch. If a section is already cracked or missing, note it and move on — a cleaner poking at failing putty just speeds the glass loosening. Wipe the grime off the surface and leave the repair to someone with a putty knife and a reason to be there.

How often does a London terrace really need this?

Twice a year does most houses. Once in late spring after the pollen drops, once in autumn before the wet sets in and the condensation season starts. A ground-floor front on a bus route wants more — quarterly, sometimes — because the brake dust just keeps coming.

Roadworks change the maths. When they had the gas main up on Grove Road the whole terrace opposite was grey inside a fortnight, frames included, and those clients went from twice a year to monthly until the works finished. If there’s scaffolding or a dig within a hundred metres, expect the sashes to load up fast.

Does the back of the house need the same schedule?

No. The back of the house is always cleaner than the front, so don’t quote the same interval for both. A garden-facing sash in a quiet Bow terrace can go a full year and look fine. The front of the same house, forty feet away on the road side, will be filthy by August.

I keep a note of which elevation faces what, and I book accordingly.