After the Builders: Refurbishment Dust
Construction dust is mineral, abrasive and far finer than household dust. What HSE says to use instead of a broom, and why one visit never finishes the job.
Published by Jerimiah, owner of J&BROS Cleaning Last updated 6 September 2026 6 min read
In short
Construction dust is mineral and abrasive rather than ordinary household dust, and its finest fraction is too small to see in normal lighting. It settles on ledges, in door tracks and in ventilation, so dry brushing puts it straight back into the air. HSE advice is to damp down with a water spray and to use an H or M class extraction unit for finer material. A post-refurbishment clean is staged, top down, and it is normally more than one visit.
Building work leaves behind something that looks like dust and behaves like grinding paste. What it actually is matters, because the normal instincts, brush it up and hoover it, are the two things that make a refurbished flat worse rather than better.
Construction dust is a mineral, not fluff
What it is made of
Household dust is mostly fibres, skin and hair. It is light, it clumps, and a cloth picks it up. Construction dust is what is left when someone cuts, drills or sands the building itself: brick, concrete, mortar, tile, plaster and timber reduced to powder.
The part you cannot see
Brick, tile, concrete and mortar all carry silica as a large part of their make-up, so cutting or drilling them produces respirable crystalline silica, and HSE’s point about that fraction is that ordinary lighting will not show it to you. That detail is the one that matters domestically. The dust you can see on a worktop is the coarse end of what is in the room. The part you cannot see is the part that stays airborne longest and travels furthest.
It has a mechanism, not just a look
This is not a nuisance category. Breathe it regularly and the diseases HSE says it can cause run from asthma through to silicosis and lung cancer.
Over 500 deaths a year
The scale of the harm
HSE’s estimate of construction workers dying from silica dust exposure annually.
A homeowner walking into a finished flat is not facing a tradesperson’s cumulative exposure. The point is that this material has a known mechanism, and it deserves a method rather than a duster.
Why it keeps coming back for weeks
Where it is actually sitting
Refurbishment dust does not settle once and stay put. It settles everywhere, including on every horizontal surface nobody looks at. Run through a flat that has just had a kitchen or bathroom done:
- Tops of door frames and skirting
- Blind headrails and radiator upstands
- Window and sliding door tracks
- Extract grilles
- The top of every unit and wardrobe
- Inside cupboards that were open while the work happened
Why the reservoirs feed the second visit
Every one of those is a reservoir. Air movement, a door closing, a fan starting, somebody pulling a blind, and a little of it comes back down onto the surfaces you cleaned. HSE’s own measurements are about the working version of this. Dry brush a concrete floor and the fine dust goes up, re-settles later, and the floor has to be cleaned again. Use the correct extraction unit instead and HSE records no resettling. Method decides whether you do the floor twice. The reservoirs are a separate problem, and they are what a second visit is for.
That is why a post-refurbishment clean is staged. You work top down, empty the reservoirs before you finish the floors, and accept that the ones you cannot reach will still be releasing after you leave.
The broom and the wrong vacuum both make it worse
The two default tools are the two worst choices, and they fail in different ways.
The broom
A broom on dry construction dust is measurably dangerous. The peaks HSE recorded for sweeping concrete dust dry arrive quickly and sit far above the workplace exposure limit for silica, which is set as an average over 8 hours. You are not sweeping the dust up. You are putting it into the air of a room you are standing in, and it lands again later.
The household vacuum
A household vacuum is quieter about it and it is still the wrong tool. These machines are built for fibres and crumbs. HSE specifies vacuum attachments fitted to an H or M class extraction unit for finer construction material, and a domestic machine is neither class, so nobody has rated it for powder this fine. The motor pays for it either way.
The method that works
The method that works is the one HSE sets out for site work, scaled down. Damp the surface before you disturb it. Use a water spray rather than a dry cloth. For the fine material, use vacuum attachments fitted to an H or M class extraction unit, which is a filtered machine built for this. Wet wipe, and change the water often.
If the building predates 2000, ask first
This one sits before the cleaning conversation. The year 2000 is HSE’s cut-off: a building put up or refitted earlier than that may contain asbestos, and the fibres come out when that material gets damaged or disturbed.
Plenty of the stock around Limehouse, Poplar and Whitechapel is a conversion or a refit of something considerably older. If a wall, ceiling, artex finish, floor covering or boiler flue is about to be opened up, that needs settling before the work starts rather than after. A cleaner arriving afterwards is the wrong person to discover it.
What a staged post-refurb clean actually involves
The order of work
The order is fixed, and it is the order because of how dust falls. Out of sequence, you clean the same surface twice.
- Waste and protection out first. Rubble, offcuts, dust sheets, protective film and masking tape. Builders’ rubble is not something a normal household collection will take, so removal has to be arranged separately.
- High level, damp. Frames, headrails, tops of units, light fittings, extract grilles.
- Tracks, channels and edges. Window runners, door thresholds, the gaps beside skirting. This is slow, and it is where a rushed job shows.
- Joinery inside and out. Cupboards, drawers, wardrobes, anywhere a door was open during the work.
- Glass last of the verticals, and never dry, because windows above ground floor level bring their own access limits on top of that.
- Carpets and soft furnishings. Fine dust settles down into pile and upholstery, below the depth surface vacuuming reaches, so hot water extraction is the sensible finish once the hard surfaces are done.
- Floors last of everything, wet, with the water changed repeatedly.
Then leave it, and do it again
Leave it a few days and do the reservoirs again, because they go on releasing after the first pass. That second visit is mostly about the reservoirs rather than a fresh start, so it is shorter than the first. The same reservoirs catch people out in a newly handed over Canary Wharf flat, where the dust is builders’ dust that nobody has lived with yet.
Booking too early means cleaning the room twice
Here is the part that loses us bookings, and we would rather say it than take the date.
Do not book the clean while any trade is still working, and not for the same day the last one finishes. One person carrying a worktop through a hallway undoes an afternoon of work on the way through. If the plumber is back on Thursday for a snag, Thursday is not the day.
Wait until the trades are done, the waste has left the building and the tools have gone. Then clean, then plan a lighter one off clean a week or two later once everything that was going to fall has fallen. That sequence gets you a finished flat, rather than one heroic visit followed by three months of finding dust on the door frames.
The numbers, and where they come from
- It is a health risk, not a mess
- HSE states that regularly breathing construction dust can cause diseases including lung cancer, asthma, chronic obstructive pulmonary disease and silicosis.
- Source
- The scale of the harm
- Over 500 construction workers are believed to die from exposure to silica dust every year, according to HSE.
- Source
- The dangerous part is invisible
- Silica is a major constituent of bricks, tiles, concrete and mortar, and the fine respirable crystalline silica generated by cutting or drilling is too fine to see with normal lighting.
- Source
- Dry brushing spikes exposure
- The workplace exposure limit for silica is 0.1 mg/m3 averaged over 8 hours. HSE reports that dry brushing concrete dust quickly produces peaks of around 1-2 mg/m3.
- Source
- Method decides whether it returns
- HSE notes that dry brushing throws fine respirable dust into the air, which re-settles later so the floor has to be cleaned again, and that with the correct extraction unit there is no resettling.
- Source
- Damp down and filter
- HSE advice for clearing construction debris is to damp down with a water spray, and to use vacuum attachments fitted to an H or M class extraction unit for finer material.
- Source
- Anything before 2000
- HSE warns that asbestos can be present in any building built or refurbished before the year 2000, and that fibres are released when asbestos containing materials are disturbed or damaged.
- Source
Common advice that is wrong
- false
“Plaster dust is just dust, a good hoover will get it.”
H or M class extraction is what HSE specifies for the fine material. Household vacuums carry neither rating.
Plaster, mortar and concrete dust is mineral, and its finest fraction is respirable crystalline silica rather than fluff. The kit HSE names for the fine material is an H or M class extraction unit, used through vacuum attachments. For the coarse debris its advice is a water spray to damp it down. H and M are rated dust classes. A general household vacuum is built for fibres and crumbs, it is neither class, and nothing about a domestic filter is specified for powder this fine. It will also wear the machine out.
Source: hse.gov.uk
- false
“Sweep the rubble out first, then clean properly.”
Damp the dust down first. HSE's peak reading for dry brushing of concrete dust runs far above the workplace exposure limit, and you are standing in that air.
Dry sweeping is the single worst thing you can do in a room full of settled construction dust. HSE measured dry brushing of concrete dust producing peak silica levels of around 1-2 mg/m3, against a workplace exposure limit of 0.1 mg/m3 over 8 hours. HSE's own instruction for site clearing is a water spray to damp down first, then a rake, shovel and bucket. Same order in a flat, and air the room out once the dust is wet rather than while it is dry.
Source: hse.gov.uk
- partly true
“One thorough visit after the builders leave will do it.”
HSE records no resettling where the correct extraction unit is used. A properly cleaned floor stays clean. The second visit is for door tracks, extract grilles and the tops of units.
One visit will make a room usable and it is most of the work. What it will not do is finish the job, though not for the reason usually given. HSE's own comparison is that dry brushing sends dust up to re-settle later, while with the correct extraction unit there is no resettling. So a properly extracted floor does not owe you a repeat. What it owes you is the reservoirs: door and window tracks, extract grilles, the tops of units and cupboards that stood open, all of which keep releasing for days as doors close and fans run. Budget a shorter second pass for those.
Source: hse.gov.uk
- false
“Book the cleaners for the day the trades finish and save a trip.”
Cutting, drilling, grinding and polishing all throw out construction dust, so a room cleaned mid-job gets cleaned twice.
This one costs us work to say. HSE says the tasks that generate respirable crystalline silica include cutting, drilling, grinding and polishing, and every one of them is still happening while a trade is on site. Clean behind that and the room is dusty again by the end of the week, so the trip is not saved, it is duplicated. Carrying materials through a hallway does the same thing more slowly. Take the later date, once every trade has genuinely finished and the waste has gone.
Source: hse.gov.uk
What we see on the job
We are a six person family team rather than an agency, so the people who walk a refurbished flat on the first visit are the same people who come back for the second. We cover each other for illness and holiday, so a booked date does not fall through. We work Canary Wharf and East London, in flats, houses and small offices, and we can often take short notice work when a handover date slips. There is no contract and no notice period, so nothing forces you to fix a schedule while the trades are still on site. If we miss something, we come back.
Common questions
Why does construction dust keep coming back after a clean?
Because most of it was never on the floor. It sits on ledges, on top of door frames, in window and door tracks, behind radiators and inside ventilation grilles, and it works its way out over days as air moves and doors open. Emptying those reservoirs is slow work, and a first visit rarely reaches all of them, which is why the job is staged rather than done in one push.
Can I just use my own vacuum on plaster dust?
For visible chunks and grit, yes, though it will wear the machine out. For the fine powder it is the wrong tool. HSE's advice for finer construction material is a vacuum attachment fitted to an H or M class extraction unit, and a household machine is neither class. Damp the surface, wipe it up wet, and hire the right unit if there is a lot of it.
Should I open the windows while cleaning up after building work?
Ventilate, yes, but do it after the dust has been damped down and taken away rather than while it is being disturbed. Moving air across dry settled dust lifts it and carries it into rooms that were clean. Shut internal doors, control the dust at source, then air the place out once the surfaces are wet cleaned.
Is dust from my neighbour's refurbishment a problem for me?
It can be. In a converted terrace or a block with shared risers, fine dust travels through service voids, letterboxes and communal corridors and lands on your side of the wall. You are unlikely to get anything like the exposure of someone working in the room, but the settling and re-settling behaves the same way, so the same staged approach works.
What about asbestos in an older East London conversion?
Treat it as a real possibility. A conversion that went up, or was last refitted, earlier than 2000 falls inside the period HSE flags for asbestos, and the fibres get into the air when that material is disturbed or damaged, so the question has to be settled before anyone opens up a wall, ceiling or floor covering, not discovered by a cleaner afterwards. If something looks wrong, stop and get advice.
How long after the builders leave should I book the clean?
After the last trade has finished and the waste has actually gone, not on the day the scaffold comes down. Cleaning around ongoing work means the same room gets cleaned twice, and only the second one counts. If a date has to move because a trade overran, move the clean rather than doing it early.
If you would rather we did it
We are a small cleaning team working across Canary Wharf and East London.
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Hot water extraction for carpets, rugs, and sofas.
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Who is behind this
J&BROS Cleaning is run by Jerimiah, who owns the business. We are a small cleaning team working across Canary Wharf and East London, and these guides are published under his name. More about us .
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