Wit, aged 51, decided to renovate his two-storey, twenty-year-old house in Bang Phli, Samut Prakan. The project turned out larger than planned: two partition walls demolished, all ground-floor tiling stripped and replaced with laminate, ceilings sanded, the entire house repainted, and the electrical system replaced. It took two and a half months.

During construction the family stayed with relatives. When the contractor handed over, Wit hired a professional cleaning crew for a full day: every surface wiped, floors mopped three times, every pane of glass cleaned. Only then did the furniture come back in.

The first week felt perfect. The house was brighter, the paint smell had faded, everyone was delighted. Then in the second week his fourteen-year-old daughter began a dry night-time cough. In the third week his wife complained of a sore throat and hoarseness every morning. By the second month Wit himself was coughing, and his 78-year-old mother, who lives with them, was struggling to breathe comfortably.

What was strange was that everyone improved when they went out and deteriorated the moment they came home. Wit began to suspect the freshly renovated house was harming his family.

He bought a particle meter and measured indoors. PM2.5 in the living room was clearly higher than outside, even with doors and windows shut and an air purifier running all day.

This is where most homeowners underestimate the problem. Renovation dust is not the same as the dust that drifts into a house normally.

• The particles are far smaller. Cutting, grinding, sanding and demolition break materials into micron-scale particles that stay airborne for hours.
• They are sharp and irritating. Cement, gypsum and wood dust have hard edges, so they irritate the airway lining far more than typical household dust.
• They carry chemicals. Paint mist, solvents, adhesives and coatings keep off-gassing for weeks after the work is finished.
• They penetrate fabric more deeply. Because the particles are so small, construction dust settles into the deep layers of sofas, mattresses and carpets, where wiping can never reach.
• It lodges in the air conditioning. Coils and ducts become reservoirs that release dust again every time the unit is switched on.

More importantly, once fine dust accumulates in soft furnishings and carpets, it becomes both food supply and shelter for dust mites in the months that follow. A short-term problem quietly converts into a long-term one.

Wit insists he paid professionals for a full day of cleaning. So why did the symptoms persist?

1. Wiping only addresses hard surfaces. Floors, walls, glass and counters were genuinely clean, but the fabric furniture brought back in was never deep cleaned at all.

2. The furniture in storage was exposed too. The plastic sheeting used during construction rarely seals completely, so fine dust worked its way in over two and a half months.

3. Sweeping and dusting re-suspend the problem. Feather dusters and brooms move dust from one place to another.

4. Standard vacuums cannot retain particles this fine. Micron-scale construction dust passes straight through a normal filter bag and out of the exhaust. The more you vacuum, the more it circulates.

5. Air purifiers only capture what is airborne. Dust settled inside a sofa or carpet stays there until someone sits down or walks across it and lifts it again.

The conclusion is simple. A freshly renovated home needs deep cleaning of every fabric item, not just a surface clean.

Wit says his renovation budget never contained this line.

Medical costs for four people. Consultations, cough medicine, antihistamines, and a chest x-ray for his 78-year-old mother that the doctor requested as a precaution.

Three air purifiers. Bought after the symptoms appeared, yet indoor particle readings fell only slightly.

The cost of not using the house. The family renovated to make the home more liveable, then began avoiding the living room, the very space they had invested the most in.

Regret and disappointment. Wit had been looking forward to evenings watching television together in the new room. Instead everyone started retreating upstairs earlier than before.

Risk to the eldest family member. This is what made him act quickly. A 78-year-old struggling to breathe in her own home is not something that can wait.

Wit booked the dust mite removal, mattress, sofa and carpet cleaning service with full disinfection from World Health Disinfection, specifying that the house had just been through a heavy renovation.

The team used the SIRENA System dust mite vacuum, which is particularly suited to this kind of work because water filtration traps every particle in water, unlike a bag vacuum which pushes fine dust straight back into the room.

They worked room by room, starting with the large living room sofa suite, then the carpets, the newly installed curtains, every mattress, every pillow, and the dining chair upholstery.

The clearest result was in the tank. The water drawn from the sofa and carpets came out a chalky grey, like cement slurry, with a thick layer of fine sediment. Wit filmed it, because he could not believe a house mopped three times still held that much.

The visit ended with medical-grade disinfection throughout, addressing the mould and bacteria that typically develop while a house sits closed up during construction.

The ideal moment is after the contractor hands over and the surface clean is finished, but before the family fully moves back in.

1. Allow paint and solvent odours to off-gas first. Roughly seven to fourteen days with ventilation.
2. Let the crew finish the hard surfaces. Floors, walls, ceilings and glass.
3. Move the fabric furniture in, then book deep extraction for everything.
4. Finish with whole-house disinfection before the actual move-in date.

For households that have already moved back in, as in Wit case, the service can be carried out immediately and works just as well.

Further reading on indoor air quality is available from the World Health Organization and Thai health guidance from the Department of Disease Control.

• Homes that have just been renovated or extended
• Condominiums just handed over by the developer
• Houses freshly repainted or refloored throughout
• Offices recently refurbished or newly occupied
• Shops and clinics finishing fit-out before opening
• Properties reopened after standing closed for a long period

In every case, deep cleaning before real occupancy reduces both short-term respiratory problems and long-term dust mite accumulation.

We already had a full deep clean. Do we still need this?

Should it be done before or after moving the furniture in?

Can paint residue and chemical odours be handled as well?

How long does a two-storey house take?

Do we need to leave during the work?

Do you serve provincial locations?

Most homeowners only start thinking about cleaning once the work is finished, which is too late for several things. Wit set out the timeline he wishes he had read beforehand.

Before construction begins. Move as much fabric furniture as possible out of the work area and wrap it in plastic sealed on every side, not merely draped over, because fine dust enters through the open underside. Agree with the contractor to partition the area with sheeting and to run an extractor fan venting outside during heavy dust-generating work.

During construction. Ask the contractor to clear dust daily rather than only at handover, and change the air conditioning filters if any units remain in use.

First week after handover. Ventilate as much as possible to clear paint and adhesive volatiles. Do not move fabric furniture back in yet.

Second week. Clean every hard surface: floors, walls, ceilings, door frames and air vents. Wash every air conditioning filter.

Third week. Move fabric furniture back in, and book the deep clean for the same week so that dust picked up during storage and transport is captured immediately.

One month later. Reassess. If symptoms persist or readings remain high in particular rooms, target those rooms specifically.

Wit stresses that the order matters more than people expect. Deep cleaning fabric furniture before the hard surfaces are clean simply allows dust from ceilings and walls to settle back onto the furniture within days.

Not all construction dust is the same. Knowing which kind your home has helps you plan accurately.

Cement and concrete dust comes from demolition, drilling and floor grinding. It is highly alkaline with sharp edges, strongly irritating to the nasal and throat lining, and it travels throughout the house and persists in fabric for a long time.

Gypsum dust from installing and sanding plasterboard is extremely light and stays airborne for hours, typically settling on high surfaces and inside air conditioning ducts.

Wood dust from built-in furniture and timber flooring may carry surface coatings, and some people are specifically sensitised to particular wood species.

Paint mist and solvents continue off-gassing for weeks, causing headaches, nausea and eye irritation even after the smell has faded.

Dust from demolishing old material can contain mould, spores and organic matter accumulated over many years, and this group provokes the respiratory system most severely of all.

In practice, a home that has been through a major renovation usually has all five at once, which is precisely why surface cleaning alone is not enough.

For post-renovation work, the deciding factor is the particle size the machine can genuinely retain, because construction dust is far finer than ordinary household dust.

We just took handover of a new condominium. Should we do this before moving in?

We already washed the air conditioning filters. Is anything else needed?

We have young children. When can they come back?

We are renovating in phases. When should we clean?

What Wit wants every homeowner to know is that an inexpensive air quality monitor became his single best handover tool, and that he used it far more systematically than simply glancing at the number.

Always measure two points simultaneously, one indoors and one outdoors, because an indoor figure on its own tells you nothing if outdoor levels happen to be very high that day.

Measure at the same times every day. He chose seven in the morning, two in the afternoon and nine at night, because those three points reflect conditions before the windows open, during daytime activity, and after activity settles.

Measure in the same position and at the same height. He marked the spot on a table, because a difference of even half a metre in height can change the reading substantially.

Run a disturbance test. This is the method he found most useful. Take a baseline in a completely still room, then walk across the carpet or sit down heavily on the sofa three times, and measure again after one minute. If the number jumps sharply, that surface is still holding a large particle load.

Wit ran the disturbance test both before and after the deep clean and found that the post-disturbance spike fell significantly afterwards, which is far more direct evidence than a daily average.

His conclusion is that homeowners planning a renovation should buy the meter before the work starts, so they have a baseline for their own house to compare against. If you only begin measuring after handover, you have no way of knowing whether the figure you are looking at is high or low for that particular home.

He adds one caution. Cheap sensors drift over time and are not laboratory instruments. Treat them as a way of comparing your own house against itself, not as an absolute measurement, and never use a single reading to make a decision. A week of readings tells you something. One reading tells you almost nothing.

For post-renovation work, the team first assesses the residual dust load on site, then sets the number of extraction passes required for each item.

The standard scope of the World Health Disinfection full dust mite removal service covers the following.

• Every mattress: deep extraction across the surface, the sides and the seams, which is where accumulation is heaviest.
• Pillows and duvets, treated individually, including bolsters and cushions.
• Upholstered headboards and fabric wall panels, surfaces close to the face that rarely appear in any cleaning plan.
• Sofas and fabric chairs, deep extracted and washed according to the fabric type.
• Carpets and door mats, extracted at depth and washed to restore the fibres.
• Every curtain panel, cleaned on the rail with no dismantling.
• Plush toys and other fabric items as specified by the homeowner.
• Medical-grade disinfection spraying to close every job.
• Complimentary with every visit: WELLGIENIC disinfectant wipes and CHEMGENE HLD4H disinfectant spray.

Service areas. All of Bangkok and the surrounding metropolitan area, including Nonthaburi, Pathum Thani, Samut Prakan, Nakhon Pathom and Samut Sakhon. Provincial locations are served by arrangement, particularly for multi-site or multi-building work carried out in one programme.

Booking and quotation. Quotations are free by phone or LINE, with no cost and no obligation. Simply describe the area, the number of rooms, the number of mattresses and the fabric items you want treated, and the team will set out the scope and expected duration before you decide.

Wit believes most post-renovation dust problems are decided long before the first wall comes down, in what the contract does and does not say. He now includes five clauses in every quotation he accepts.

Daily dust clearance rather than a single clean at handover. Written as a daily obligation, not a courtesy, because dust that sits for weeks migrates into every part of the house.

Physical partitioning of the work zone using sheeting taped at the floor and ceiling, with a specified minimum, rather than leaving it to the crew judgement on the day.

Negative pressure ventilation during heavy dust work, meaning an extractor fan discharging outside whenever cutting, grinding or demolition is taking place.

A named handover checkpoint for air quality, even if it is only agreed readings taken before final payment. Wit found that simply including it changed how carefully the crew worked.

Protection standards for stored furniture, specifying fully sealed wrapping rather than draped covers, and stating who is responsible if items are found contaminated afterwards.

He is careful to say none of this makes a contractor an adversary. Most crews are willing to work this way when it is agreed at the start and priced in, and several told him afterwards that they preferred it because it reduced the amount of cleaning they had to do at the end.

What causes problems, in his experience, is raising these expectations halfway through the job, when the schedule is fixed and the price is set. By then nobody has room to accommodate them, and the homeowner ends up absorbing the consequences.