A Story from the Field: A Message in the Residents' LINE Group at 1 a.m.

Orn manages the juristic person office of a condominium in Din Daeng that is more than twenty years old. The building has eight floors and almost two hundred units. Some owners have lived there since it opened; others are older residents living alone, and many units are rented to office workers who like being close to the city. During the October 2026 floods, water stood in the soi for several days. The ground floor, where the shared trash room, the water pump room and the car park are, took in water about a hand-span deep.

While the soi was flooded, the garbage trucks could not get in for almost a week. Bags from every floor kept coming down the trash chute and piling up in the trash room until it overflowed. Some bags split open, and garbage juice mixed with floodwater spread across the floor. When the water finally drained, the housekeepers hauled everything out and hosed down the room. Everyone assumed the problem was over.

Three days later, the residents' LINE group would not stop pinging. "The fifth-floor corridor smells like a burst pipe." "I opened the cabinet under my sink and the smell came straight up." "The lift stinks; my son threw up in it." The latest message arrived at one in the morning, from an elderly resident on the seventh floor who could not sleep because the smell was drifting into her bathroom. The next morning Orn walked the entire building. The smell was strongest in the ground-floor trash room, at the chute doors on each floor, and around the pipe shafts that run the full height of the building.

"That was when we understood the trash room was not just a ground-floor problem," Orn says. "An old building has lots of paths for air to travel upward. Whatever smell is stuck downstairs gets pulled up to every floor."

Note: this is an illustrative scenario based on problems commonly seen in older condominium buildings after flooding. It does not refer to any news report or to statistics from any agency.

Why a Ground-Floor Trash Room Smell Shows Up on the Top Floors

The stack effect. Tall buildings with vertical openings, such as trash chutes, pipe shafts, stairwells and lift shafts, naturally move air upward, especially when the air at the bottom is warmer and more humid. Odors from the trash room are drawn up those channels and released wherever there is a gap: a chute door, a loose shaft panel, a bathroom vent, or the lift doors.

Residue soaked into porous materials. In older trash rooms the concrete floor is often unsealed, the paint is peeling, grout lines are open, and the door frames may be wood. Those materials absorb the mix of garbage juice and floodwater. Hosing down the room removes what is on the surface, but what has soaked in keeps releasing odor every day.

A trash chute that has never been cleaned. The inside walls of a chute collect years of residue. When the room below overflowed, liquid splashed up the chute; add post-flood humidity, and bacteria on those walls multiply quickly. Every time a chute door opens, a puff of that air comes out.

Dry or damaged drain traps. In units left empty during the flood, the water in floor drain and sink traps can evaporate. Without that water seal, sewer gases come straight back into the room. If a pipe is cracked or leaking, or the building's wastewater treatment tank has overflowed, a plumber or wastewater system specialist must inspect it. Disinfection cannot fix a broken pipe.

Humidity that never quite leaves. Ground floors in older Bangkok buildings are often poorly ventilated, and after a flood the concrete slab, the walls and the space behind the bin racks stay damp for a long time. Damp air carries odors further and keeps feeding mold and bacteria. That is why a room that looked clean on the day it was hosed down can smell worse a few days later, and why drying and ventilation are as important as cleaning itself.

What the Juristic Person Has to Deal With

Health of residents and staff

A flooded trash room is a high-risk area: food waste, garbage juice, and floodwater that may carry germs from drains. Those germs can cause diarrhea, and rats that gather around trash rooms raise the risk of leptospirosis. Housekeepers and staff who move the garbage should wear rubber gloves, boots and a mask. Residents with allergies or asthma, young children and older adults may be irritated by odors and damp air more easily than others. This is general information, not medical advice; anyone who feels unwell should see a doctor.

Relationships with residents

A common-area smell affects everyone at once, so frustration spreads quickly in chat groups. If the juristic person does not explain clearly what is being done and when, residents may assume nothing is happening, and complaints can escalate to the annual general meeting.

Property values and rentals

Older condominiums compete on location and price. But if a prospective tenant smells something unpleasant in the lobby or in the lift, the viewing is effectively over. Owners who rent out their units feel this immediately and will press the juristic person for a fast fix.

Budget and accountability

Juristic persons spend common funds and must be able to justify them. Paying for repeated cleanings that do not solve the problem, or for fragrance systems that only mask it, is hard to defend. A clear, staged plan with a documented scope is easier to present to the committee.

Fixes Many Buildings Try That Do Not Work

• High-pressure hosing: it removes surface grime but pushes dirty water deeper into cracks and joints and adds moisture to a room that is already damp.
• Pouring in lots of bleach: the harsh chlorine smell travels up the shafts just like the garbage odor, triggering a new wave of complaints, and it still does not reach places like the inside of the chute.
• Automatic fragrance dispensers: they mask the odor briefly, but mixed with garbage smell many residents find the result worse.
• Sealing the chute doors permanently: this reduces odor on upper floors a little, but residents must carry their trash down, and the source on the ground floor is still there.
• Repainting the trash room right away: painting over damp, stained walls leads to blistering and mold under the new paint later.

A Plan for the Juristic Person: From the Source to Every Floor

1. Survey and map the smell. Walk every floor and note where the odor is strongest: chute doors, shaft panels, common toilets, lifts. Try to separate odors that come from the trash room from those that come from wastewater pipes.
2. Have a plumber check pipes and the treatment tank. If a pipe may be cracked or leaking, or the treatment tank may have overflowed, fix that first. Otherwise any disinfection will only help temporarily.
3. Remove waste and scrub away organic residue. Take out every remaining bag, wash the bins, scrub the floor and walls to remove organic film, then let the room dry.
4. Refill drain traps. Ask residents to run water into floor drains and sinks in their own units. For empty units, ask owners or key holders to help.
5. Disinfect common areas. Fog the trash room, the chute, the lifts, the ground-floor lobby and any corridor with odor.
6. Ozone-treat the trash room and closed spaces. This breaks down odor molecules that have soaked into materials and deals with mold spores in damp rooms.
7. Ventilate, re-check and set a routine. Schedule regular trash room cleaning and odor checks so the problem does not quietly return.

The WHD Solution: Disinfection Fogging Plus Ozone Treatment for Condominium Common Areas

World Health Disinfection (WHD) offers a disinfection fogging service and an ozone treatment service for buildings affected by flooding, including condominiums and older residential buildings in Din Daeng, Huai Khwang, Phaya Thai and nearby districts. Work is planned with the juristic person so that residents' daily lives are disrupted as little as possible.

Disinfection fogging uses CHEMGENE HLD4H through an ultra-low-volume (ULV) fogger. The fine droplets drift into trash room corners, under bin racks, along door frames and into the accessible parts of the chute. In lifts and lobbies the focus is on high-touch surfaces such as buttons, handrails and door handles.

Ozone treatment uses an ozone generator in the trash room and other closed spaces that can be kept empty. Ozone gas breaks down odor molecules soaked into walls and floors and acts on airborne mold spores, something hosing and fragrance cannot do.

How we work with the juristic person

1. Site survey. The team inspects the trash room, chute, lifts and the places residents have complained about, and points out anything a plumber needs to fix first.
2. Advice on waste removal and mud cleanup. So that surfaces are ready to be disinfected.
3. Scheduling. For example, late morning on a weekday when most residents are at work, with advance notice that the trash room or one lift will be closed for a while.
4. Disinfection fogging. Trash room, chute, lifts, ground-floor lobby and affected corridors.
5. Ozone shock treatment. The trash room and designated closed spaces are sealed, signs are posted, and no people or pets may be inside.
6. Ventilation. Doors and exhaust fans are opened until there is no ozone smell before the area reopens.
7. Follow-up and care advice. The team checks on the odor in the following days and recommends a suitable cleaning routine.

10 Reasons Din Daeng Condominium Managers Choose WHD

1. The work starts by finding the source of the smell, not by spraying everywhere at random.
2. CHEMGENE HLD4H is used on trash room surfaces and shared touch points.
3. ULV droplets reach dead corners and narrow gaps.
4. Ozone odor removal replaces fragrance masking.
5. Work is timed to disturb residents as little as possible.
6. You are told what a plumber needs to fix first, so you do not pay twice.
7. Building equipment such as lift systems and CCTV is protected.
8. Owners who want their own units treated can be served too; see ozone disinfection for homes.
9. Add-on services such as mosquito spraying around the building after the water recedes are available.
10. The juristic person gets clear information to share with residents and the committee.

What Building Managers Tell Us

"What helped most was knowing the right order: get a plumber to check the pipes, clear the waste, scrub, and only then fog and ozone-treat. We posted in the residents' group in advance how many hours the trash room would be closed, and everyone cooperated. The smell in the lifts and corridors dropped a lot, and the late-night complaints stopped."
- Juristic person manager of a condominium in Din Daeng (illustrative field scenario)

Sample Notice to Residents (Adapt as Needed)

"Dear co-owners and residents, the juristic person will carry out disinfection fogging and ozone treatment of the trash room, the trash chute and ground-floor common areas on the date and time stated. During this period, please do not use the trash chute and take your garbage to the temporary collection point at the front of the building. We also ask you to run water into the floor drains and sinks in your unit to refill the drain traps. If you live with older family members, young children or pets, please stay away from any area marked with a no-entry sign until it reopens."

A short notice like this answers the questions residents usually ask, shows that the juristic person has a plan, and reduces the number of messages the office has to answer during the work.

Beyond the Trash Room: Other Common Areas to Check

When residents complain about a smell, the trash room is usually the main culprit, but in an older building that has taken in floodwater it is rarely the only one. While planning the work, it makes sense to walk through the other shared spaces on the ground floor and basement as well.

• Lift cars and lift pits. If water reached the lift pit, mud and moisture can remain at the bottom of the shaft. Lift pits must be handled by the lift maintenance company, but the lift cars themselves, with their carpets, wall panels and buttons, can be cleaned and disinfected once the lift is confirmed safe to use.
• The water pump room. Pump rooms are often small, closed and damp. After a flood, mold can grow on walls and wooden doors. Electrical safety comes first: a qualified electrician should check pumps and panels before anyone cleans the room.
• The car park and loading area. Mud left on the floor dries into dust that is tracked into the lobby and lifts. Clearing it and disinfecting the floor reduces both odor and dirt brought inside.
• Ground-floor common toilets and staff rooms. These rooms often have floor drains whose traps dried out during the flood, and they are easy to overlook.
• The lobby furniture and notice boards. Fabric sofas and pin boards near the entrance can absorb damp air and smell musty for weeks.

Handling these spaces in the same visit as the trash room saves time and avoids a situation where one area is fixed while the smell lingers in another.

What to Prepare Before the Committee Approves the Work

Most juristic persons need committee approval before spending common funds. Preparing a short, clear package makes that meeting faster and avoids second-guessing later.

1. A list of complaints by location and date, taken from the residents' chat group and the front desk log. This shows the scale of the problem.
2. Photos of the trash room, chute doors and other affected areas, taken during your walk-through.
3. The plumber's findings, stating whether pipes or the treatment tank need repair and whether that repair has been done.
4. The proposed scope of disinfection and ozone treatment, listing which rooms, how they will be sealed, and how long each area will be closed.
5. A resident communication plan, including the notice text and where garbage will go during the work.
6. A follow-up plan, describing how the office will check odor afterwards and what routine cleaning will follow.

With this information, the committee can see that the money is going to the cause of the problem, not to another round of masking it.

Keeping It from Coming Back: A Simple Routine for Older Buildings

• Weekly: wash bins and the trash room floor, check that the floor drain in the room is flowing, and keep the door closed between collections.
• Monthly: walk every floor and check chute doors for odor; wipe chute door handles and lift buttons with a disinfectant such as CHEMGENE 750 ml spray.
• Before the rainy season: check that the ground-floor drains and pumps work, and prepare a plan for storing garbage if trucks cannot reach the building.
• After any flood: follow the plan above, starting with plumbing checks and waste removal, before choosing disinfection and ozone treatment.

Frequently Asked Questions

Q: After ozone treatment in the trash room, will ozone rise through the shafts like the garbage smell?
A: The team seals off the treated area, uses a controlled dose, and does not treat shafts that connect directly to occupied units. After treatment the area is ventilated to the outside before it reopens.

Q: Do residents have to leave the building during the work?
A: Generally not for common-area work in spaces that can be sealed off, but residents must stay out of signed areas until they reopen.

Q: Can the whole trash chute be disinfected?
A: The parts accessible from the trash room and each floor's chute door can be fogged. If the residue inside is very heavy, a specialist chute-cleaning contractor may also be needed.

Q: What if the smell comes from a unit's wastewater pipes?
A: Refill the drain traps first. If the smell continues, have a plumber inspect it, because it may be a pipe or treatment system problem that needs repair.

Q: How often should this be done?
A: It depends on the building and how garbage is managed. Some buildings treat after a major event and maintain with regular trash room cleaning; the team can suggest a suitable schedule.

Q: An owner wants their own unit treated too. How do they arrange it?
A: They can contact the team directly by phone or LINE, and inform the juristic person according to the building rules.

Stop the Trash Room from Being the Source of Every Smell in the Building

Condominium juristic persons in Din Daeng and nearby areas can talk to the WHD team about planning common-area disinfection and ozone treatment.

See Disinfection Service - Click Here

Book Ozone Treatment - Click Here

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related Links

• Ozone odor and chemical residue removal
• Ozone disinfection for homes
• Mosquito spraying service
• All articles
• External source: WHO: Floods fact sheet and Department of Health, Thailand

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Keywords: condo trash room smell after flood, pipe shaft odor, condominium juristic person, common area disinfection, trash room ozone treatment, old condominium, Din Daeng Bangkok 2026