Expat Family Delays Move-In 14 Days and Asks for a Rent Cut Over a Rental Townhome's Wood Floor Varnish Smell

The floors gleamed like new, but the wood floor varnish smell trapped inside a closed-up townhome nearly cost a landlord a two-year lease. Here is what that smell really is, why the usual fixes fall short, and how ozone paint odor removal with the Master Ozone Generator brought the tenants back.

A Thursday evening, a front door opens, and a two-year lease starts to wobble

This story is a composite based on situations we commonly see; names and places are fictional.

A wood floor varnish smell is one of those problems landlords rarely see coming. On the day the flooring crew packs up, the floor looks flawless. But for a tenant walking in for the first time, the sharp chemical odor hanging in a closed house is the first thing they notice, long before they admire the shine.

Sunanta, 56, is a retired bank officer whose main income now comes from renting out property. She owns a 16-year-old, three-storey townhome in a quiet Bang Na housing estate we will call Suan Chan Ruang. It has about 190 square metres of living space, comes fully furnished, and features her pride and joy: padauk parquet flooring in the living room, all three bedrooms and the upstairs landings, roughly 118 square metres in total. After the previous tenants moved out, the floor was scratched and sun-faded, so she decided to have it fully refinished.

Soon afterwards, a relocation company brought a Danish family to view the house. Mikkel is an engineer transferred to a factory near Bang Pakong. His wife, Signe, looks after their 8-year-old son and 3-year-old daughter, who has a history of respiratory allergies. The family loved the place at first sight: it was close to the children's international school, and the warm wooden floors reminded them of home.

A two-year lease at 42,000 baht a month was signed, with deposit and advance rent totalling 126,000 baht. Move-in was set for Saturday, 1 August, because Mikkel's employer was only paying for their serviced apartment until 31 July.

Twelve days of floor work in a sealed-up house

Over 12 days from 16 July, the crew sanded the old floor back in three passes, filled the gaps with wood filler, applied a sealer and then laid down three coats of solvent-based polyurethane (PU) floor varnish. They also repainted the skirting boards and stair railing with oil-based paint thinned with paint thinner. The bill came to 88,500 baht, and the final coat was applied on Tuesday, 28 July, just four days before handover.

It was the rainy season, with downpours most afternoons, so Sunanta kept every window shut against rain and burglars. New blackout curtains were hung, three new mattresses were delivered to the bedrooms, and nobody noticed that the crew had left two part-used cans of thinner and a bag of paint rags in the storage cupboard under the stairs.

The 12 minutes that changed everything

At 5 p.m. on Thursday, 30 July, Praewa from the relocation company brought Signe and her daughter for the pre-move-in inspection. The moment the door opened, a sharp smell somewhere between turpentine and thinner hit them in the face. Signe paused on the threshold and asked quietly, "Is it safe for the kids?"

Within five minutes her daughter was rubbing her eyes and coughing. Up in the children's bedroom on the third floor, the hottest room in the house, the smell was even stronger. Signe's eyes were watering and her head was pounding. They lasted just 12 minutes before heading back to the car.

At 9:40 that night, an email arrived from the relocation company, with the HR department of Mikkel's employer copied in. It was polite but firm. The tenants asked the landlord to:

• Postpone move-in by at least 14 days until they could be confident about the indoor air quality
• Cover 14 extra nights of accommodation at 3,400 baht a night, a total of 47,600 baht
• Reduce the rent by 4,000 baht a month for 12 months, another 48,000 baht
• Failing that, they would consider invoking the lease clause on the property not being fit for occupancy

Together, that came to almost 100,000 baht, before counting the rent lost while the house sat empty. Praewa also mentioned, a little awkwardly, that the same employer would be relocating several more families next year, and that this incident would go on the property's record.

Four days of trial and error

Sunanta threw open every window, set up four fans, placed ten bags of bamboo charcoal around the house, left bowls of coffee grounds in every room and sprayed lemon air freshener. But every afternoon the rain forced the windows shut again, and every night the house had to be locked up. The flooring contractor reassured her by phone: "Give it two or three weeks and it'll be gone."

By Monday, 3 August, the living room was slightly better. The third-floor bedrooms, the wardrobes, the new curtains and the mattresses, however, still smelled strongly, and the lemon spray had turned the odor into an even worse mix. She knew that "just wait a bit longer" was not an answer a family with an allergic toddler would ever accept.

Why a wood floor varnish smell hurts rental property owners more than they expect

For anyone renting to expat families, a lingering wood floor varnish smell is never a small issue. It hits four areas at once.

1) Health: young children and allergy sufferers feel it first

• Fumes from varnish and thinner can cause headaches, dizziness and nausea, plus irritation of the eyes, nose and throat
• People with allergies or asthma may experience flare-ups in closed rooms with concentrated fumes
• Young children, older adults, pregnant women and people with health conditions are more sensitive to indoor air pollution, and toddlers spend much of their time close to the floor, right at the source
• Longer-term exposure to volatile chemicals is also a recognised health concern

2) Money: every day of delay has a price

• Lost rent while the tenants wait, roughly 1,400 baht a day for this house
• Temporary accommodation costs and rent discounts that add up to a large sum over a year
• If the lease is cancelled, months of searching for new tenants plus another agent's fee

3) Reputation: the expat rental market is a small world

• Relocation companies keep records on properties and landlords, and one bad handover can mean no more referrals
• Expat parents talk to each other constantly, especially in international school communities

4) Trust: "If the smell isn't sorted, what else isn't?"

• Tenants start wondering whether the renovation was rushed and safety overlooked
• "It'll go away soon" sounds more like brushing off responsibility than solving a problem
• A tenancy that starts with suspicion is much harder to renew

What is that smell really? VOCs from wood floor varnish, explained

What Signe smelled was not "new wood". It was volatile organic compounds (VOCs), a group of chemicals that evaporate into the air at room temperature. They are found in oil-based paints, thinners, lacquers and many types of coatings.

Where the odor in Sunanta's townhome came from

• Solvent-based PU floor varnish: resin dissolved in solvents. Once it is spread on the floor, those solvents gradually evaporate as the film dries.
• Sealer and wood filler: these soak into the timber and the joints between parquet blocks, then slowly release vapor from below the surface.
• Oil-based paint on skirting and railings: keeps giving off solvent for days after application.
• Thinner cans and rags under the stairs: an active source that keeps releasing fumes for as long as it stays in the house.

"Dry" does not mean "done off-gassing"

A varnished floor may be dry enough to walk on within hours or a day, but full curing usually takes much longer. During that time, solvent still trapped in the film and in the wood keeps seeping out. This is called off-gassing.

Freshly sanded parquet makes the wood floor varnish smell more persistent than on many other floors, because the bare timber absorbs finish deeply and the joints between thousands of small blocks hold pockets of varnish across the whole room.

Why a closed house smells worse, not better

• No air exchange: vapor released every hour stays trapped, so concentrations build up.
• Heat under the roof: higher afternoon temperatures speed up evaporation, which is why top-floor bedrooms often smell the worst.
• New soft furnishings act like sponges: curtains, foam mattresses and built-in wardrobes absorb fumes and release them again later.

Why the usual fixes fail before handover day

1. Opening windows and running fans does help, but it takes days or weeks. Rain and security meant the windows could only be open part of the day, and wardrobes and upstairs bedrooms got almost no airflow.
2. Air fresheners and perfume only mask the smell. They do nothing to break down VOCs, and the layered scents can leave people feeling even more light-headed.
3. Charcoal, baking soda and coffee grounds have a tiny absorption capacity compared with the vapor coming off more than 118 square metres of freshly varnished floor.
4. Home air purifiers are mostly designed for a single small room, not a three-storey house, and their filters can saturate quickly under heavy fumes.
5. Waiting it out is not an option when the lease has a move-in date and a family is living out of suitcases in temporary accommodation. Every day of waiting costs money.
6. Mopping with cleaning products will not pull solvent out of the timber any faster, and the curtains, mattresses and wardrobes that absorbed the odor will keep releasing it anyway.

The solution: WHD ozone paint odor and chemical residue removal with the Master Ozone Generator

With time running out, Sunanta needed a way to tackle the wood floor varnish smell throughout the whole house, quickly, and with evidence she could show her tenants. That is why she chose the ozone paint odor and chemical residue removal service from World Health Disinfection (WHD).

How ozone works

The Master Ozone Generator releases ozone gas (O₃), mimicking the way nature purifies air. Ozone oxidises and breaks the molecular bonds of odor-causing compounds, chemical vapors (VOCs) and germs at the source. In other words, it destroys odors rather than covering them up.

Once the cycle is complete, ozone naturally decomposes back into oxygen (O₂), leaving no chemical residue behind. And because it is a gas, it reaches places fans cannot: the joints in parquet, the inside of wardrobes, the space behind curtains and every dead corner.

Real before-and-after TVOC readings on site

WHD is one of the few providers in Thailand that shows TVOC (Total Volatile Organic Compounds) reduction results measured at real job sites. Readings are taken with an AM1310 meter, backed by calibration documents: a KIMO PT100 SC0110 adjusting certificate and a BR-SMART certificate of calibration. For a landlord, that means hard data that can be forwarded straight to tenants and relocation agents.

Important conditions before treatment

• Control any active source first: remove leftover thinner, paint cans and solvent-soaked rags from the property.
• Let the varnish dry for the time the manufacturer specifies. Ozone treatment then deals with the accumulated and residual odor and VOCs.
• The space must be closed and unoccupied: people, pets and plants stay out for the entire cycle.

After the process and ventilation, the space is typically ready to use within about 2 hours.

10 reasons rental owners choose ozone treatment for a wood floor varnish smell

1. It breaks down odor at the source

Ozone attacks the vapor molecules themselves. Instead of lemon scent layered over thinner, tenants get a house where the chemical smell has genuinely been reduced.

2. It reaches parquet joints, wardrobes and dead corners

As a gas, ozone spreads into the gaps between wood blocks, inside built-in cabinets and under the stairs, all places a fan simply cannot reach.

3. No chemical residue

Ozone chemical residue removal finishes with ozone reverting to oxygen, so nothing new is left on a freshly varnished floor.

4. Measured TVOC results you can share

Before-and-after readings with calibration documents turn a negotiation based on feelings into one based on data, the kind of evidence relocation companies and HR teams understand.

5. Fast enough to save the move-in date

The space is usually ready within about 2 hours after the process ends. Treat in the morning, and tenants can come back to view the next day.

6. Covers multi-storey homes

The Master Ozone Generator handles large areas, and the team plans each cycle around the volume of every floor.

7. Helps with odor absorbed by curtains and mattresses

Soft furnishings that soaked up fumes are treated in the same session, reducing the chance of the smell creeping back after the tenants move in.

8. Reduces mustiness and mold in a shut-up house

Homes left closed through the rainy season often develop a musty smell. Ozone also helps reduce musty odors, germs and mold in enclosed spaces during the same treatment.

9. Trained technicians who assess the site first

The team inspects the property and removes or covers ozone-sensitive items such as artworks, natural rubber and certain sensitive electronics before starting.

10. Protects your long-term tenants and your property's reputation

Getting professional paint odor removal after renovation done before move-in reduces the risk of a year of rent discounts or a lost tenancy, and keeps your property in good standing with relocation agents.

Before / After ozone treatment in Sunanta's townhome

How the WHD team works

1. Site survey and TVOC check at the worst-smelling points, such as upstairs bedrooms, stairwells and the inside of wardrobes.
2. People, pets and plants leave the area, and ozone-sensitive items are removed or covered.
3. The space is closed off and the Master Ozone Generator is set up, with cabinet doors and drawers opened so ozone can reach inside.
4. The cycle runs according to room volume, floor by floor or zone by zone as planned.
5. Ozone is left to decompose and the area is ventilated before anyone goes back in.
6. TVOC and odor are re-checked at the same points for a like-for-like comparison.
7. The space is handed back, typically ready to use within about 2 hours after the process ends.

How the story ended

The WHD team surveyed the townhome on Tuesday, 4 August, taking TVOC readings in the living room, the stairwell, each bedroom and inside the wardrobes. Their first recommendation had nothing to do with ozone: get the thinner cans and paint rags out of the house, and have the flooring contractor confirm the varnish had dried for the time stated by the manufacturer.

On Wednesday, the technicians moved the potted plants outside, took down an oil painting and removed a rubber-backed rug. They opened every wardrobe, drew back the curtains, stood the mattresses on their sides to expose more surface, and then treated the house one floor at a time. Once the ozone had decomposed and the rooms had been ventilated, the TVOC readings at every point were lower than before treatment, and the sharp chemical smell was noticeably reduced.

Sunanta sent photos of the before-and-after readings, together with the meter's calibration documents, to Praewa. On Saturday, 8 August, Mikkel and Signe came back with both children. This time the family stayed for about 45 minutes, and their daughter happily ran around the third-floor bedroom. Signe said she could still pick up a faint woody smell here and there, but nothing like the harsh fumes of the first visit.

Both sides agreed on a move-in date of Monday, 10 August, nine days later than planned. As a goodwill gesture, Sunanta covered five nights of accommodation, while the rent stayed at 42,000 baht a month as per the lease. She also suggested the family air the house out regularly during the first few weeks, as newly finished floors can continue to cure for some time.

Tips to prevent a wood floor varnish smell at your next renovation

• Choose low-VOC or water-based floor finishes where they suit the use of the space.
• Build curing time into the schedule according to the manufacturer's guidance, and never let the final coat land right before handover.
• Ventilate every working day and make sure the crew removes thinner, paint and rags when they leave.
• Install curtains and deliver new mattresses last, so soft furnishings do not soak up fumes.
• Book ozone treatment before the tenant inspection and keep the TVOC readings with your handover report.

Frequently asked questions

Do we need to leave during the ozone treatment?

Yes. People, pets and plants must stay out of the area for the entire cycle. You can go back in only after the ozone has decomposed and the space has been ventilated.

How long does it take?

It depends on the size of the property and how strong the odor is. After the process ends, the space is typically ready to use within about 2 hours.

Does ozone leave anything behind?

Ozone naturally breaks down back into oxygen, so there is no chemical residue. The team waits for it to decompose and ventilates the area before handing it back.

What size of space is it suitable for?

Anything from a condo unit, townhome or multi-storey house to offices, warehouses and factories. Each cycle is planned around the volume of the space.

Can ozone damage a freshly varnished wood floor?

The team assesses the site first and recommends treating only after the varnish has dried for the manufacturer's stated time. Ozone-sensitive items are removed or covered before work begins.

What if the odor source is still active?

Deal with the source first: remove leftover solvents and rags, finish any remaining coating work and ventilate. Ozone treatment is then scheduled when the space is empty to remove the accumulated odor and VOCs.

Will the smell be 100% gone?

Ozone clearly reduces accumulated odor and vapor, which you can see in the before-and-after TVOC readings. Materials that are still curing may give off a faint smell for a while, so ongoing ventilation remains important.

Related services and resources

• Ozone Cleaning Service
• Residential Ozone Disinfection
• Disinfection Spraying Service
• US EPA: Volatile Organic Compounds' Impact on Indoor Air Quality
• WHO: Air Quality, Energy and Health

Floors refinished? Don't let the smell cost you your tenants

Talk to the WHD team about ozone paint odor and chemical residue removal, with before-and-after TVOC readings measured on site.

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com
88/268 Kanlapaphruek Road, Bang Khae, Bangkok 10160, Thailand