Where the 2026 Lak Si Flood Hit Office Areas, and Why Office Disinfection Spraying Matters

The details below come from dated Thai PBS reports. Depths were measured at the time of reporting, and conditions may have changed.

• Ngam Wong Wan Road: the BMA measured 12.5 centimetres on 26 September 2026, with flooding starting at 22:25 on 25 September.
• Chaeng Watthana Road: 10.3 centimetres on 26 September 2026.
• Community near Thung Song Hong Police Station: water about 50 centimetres deep in front of homes.
• Vibhavadi Rangsit Road in front of Thai PBS: on 27 September 2026, still flooded too deep for small cars along roughly 2 kilometres; the report said road improvement works were obstructing drainage.

Across Bangkok, heavy rain on 25 and 26 September 2026 dropped more than 300 millimetres in about 48 hours, and the BMA declared all 50 districts disaster zones on 26 September (Thai PBS). Flooding points rose from 43 on the evening of 25 September to 135 on 27 September (Naewna). On 6 October the Department of Disaster Prevention and Mitigation reported about 329,000 Bangkok households affected (Bangkok Biz News), and its 06:00 report on 5 October 2026 listed 26 provinces plus Bangkok and 1,270,151 households nationwide (Daily News).

Lak Si is home to government agencies, private offices and commercial buildings along Chaeng Watthana, Vibhavadi Rangsit and Ngam Wong Wan. Road depths were mostly ten-plus centimetres, but water that lingers for days mixes with sewer overflow and runs into car parks, entrances and ground floors. Staff, housekeepers, guards and couriers who kept coming in during that time tracked water and mud into the workplace every day. Buildings where water entered the ground floor directly face an even bigger job.

A Typical Scenario: The Monday Everyone Came Back

Note: This is an example case based on situations commonly seen in offices after street flooding. It does not describe any specific company or person.

Ton is the administration manager of a mid-sized company renting two floors in a building on Chaeng Watthana Road, with about eighty staff. While the road outside was flooded and many routes were blocked, most employees worked from home, and only the IT team and a few housekeepers came in. Water entered the building's ground-floor car park, and in the document store on the same level several cardboard boxes got wet.

Once the water receded and a return date was set, Ton walked the office the day before. No water had entered the workspace directly, but the carpet tiles at the office entrance were streaked with dirty footprints. The document store smelled damp, with dark spots starting at the base of the walls. The ground-floor toilets smelled of drains, and the pantry fridge, unused for days, needed clearing. Several staff had messaged that they had colds after wading home.

Ton pictured Monday: eighty people walking through the same door, pressing the same lift buttons, tapping the same card reader, sitting in the same meeting room and using the same coffee machine. If viruses or bacteria remained on those surfaces, an outbreak could put several people on sick leave at once, just as the post-flood backlog piled up. She needed to propose to management how to prepare the office before full reopening.

Her challenge is shared by many offices in Lak Si and nearby areas. They need more than visible cleanliness. They need a process they can explain to staff, showing how the company prepared the space so everyone can return with confidence.

Office Risk Points Facilities Teams in Lak Si Should Check

An office is an enclosed space where many people spend eight to ten hours a day sharing equipment and rooms. After a flood, these areas deserve special attention:

• Building entrance, lobby and reception: wet shoes, doormats, glass doors and visitor badge kiosks are where street germs come in first.
• Card readers, fingerprint scanners and turnstiles: touched by everyone, often several times a day.
• Lifts and stairs: buttons, handrails and walls in small enclosed spaces.
• Desks, keyboards, mice and phones, especially with hot-desking, where several people share one desk.
• Meeting rooms: tables, chairs, remote controls, whiteboard markers and video-conferencing equipment passed hand to hand.
• Pantry and canteen: fridge handles, microwaves, coffee machines, water dispensers and sinks, directly linked to food and drink.
• Toilets, particularly ground-floor ones where sewage may have backed up during the flood.
• Document stores, storerooms and car parks: rarely visited and easily forgotten, yet damp and wet cardboard let mould grow fast.
• Carpet tiles and partition walls: absorbent materials that grow mould and smell musty if they do not dry in time.

Shared and hot-desk setups need extra thought

Many Lak Si offices now run flexible seating, where staff book any free desk each day. That is efficient, but it means one keyboard, mouse, desk surface and chair may be used by several people in a single week. After a flood, when some employees return with colds and others are still worried about their health, shared desks become a weak point. Facilities teams can reduce the risk by asking staff to clear desks completely at the end of each day so surfaces can be wiped, by providing disinfectant wipes at each desk cluster, and by keeping a few fixed desks for people who prefer them during the recovery period. The same thinking applies to shared meeting-room equipment such as remote controls, conference phones and whiteboard markers, which should be wiped between bookings for the first few weeks back. These small habits, combined with a professional spray of the whole floor before reopening, give staff a visible sign that the company has taken reasonable steps to protect them.

Germs to Watch in the Office After a Flood

WHO and the US CDC note that floodwater can carry sewage and germs, and advise cleaning and then disinfecting surfaces it touched. In offices, the germs fall into two groups: those that arrive with the water, and those that spread between people when everyone returns at once.

Germs that come with floodwater

• Sewage bacteria such as E. coli and Salmonella, carried on shoes and suitcase wheels onto floors and carpets, then onto hands, causing diarrhoea.
• Leptospira, the cause of leptospirosis, found in water contaminated by rat urine, especially in car parks and refuse areas. Anyone with high fever and calf pain after wading should see a doctor.
• Mould and musty odours on carpet, partitions, ceilings and document boxes. CDC advises drying within about 24 to 48 hours to reduce mould; spores can trigger symptoms in staff with allergies or asthma.

Germs that spread between staff

• Respiratory viruses such as influenza, RSV and COVID-19. During the rains and after wading, many people feel unwell, and returning together to air-conditioned rooms makes spread through droplets and surfaces easier.
• Gastrointestinal viruses such as norovirus, which spread easily via hands, shared toilets and pantries.

According to WHD's service information, CHEMGENE HLD4H is stated to be broad-spectrum against viruses, bacteria and fungi. Organisms listed on the company's pages include COVID-19, RSV, influenza H1N1, H5N1, hand, foot and mouth virus, norovirus, Salmonella and mould, with a stated efficacy of 99.99%. E. coli and Leptospira are not on that list, so this article claims no organism-specific result; they belong to the bacteria group the product says it covers. Companies wanting test documents for a specific organism can ask WHD directly.

Remember: staff with fever, muscle pain, severe diarrhoea or an inflamed wound after wading should see a doctor and rest as advised. Office disinfection treats surfaces and spaces; it is not medical treatment.

The Business Cost of Reopening Without Preparation

• Staff health: a respiratory or stomach bug at work can spread to several people within days.
• Productivity: post-flood backlogs are already heavy; simultaneous sick leave delays work further.
• Morale and trust: employees who just coped with flooding at home want to know the workplace is safe, and a clear plan reassures them.
• Assets: mouldy carpets, partitions, furniture and documents are permanently damaged and may mean lost records.
• Client impressions: visitors notice musty smells and cleanliness immediately.

Why Routine Housekeeping Falls Short After Street Flooding

1. Daily duties already fill the day: rubbish, toilets and pantry upkeep leave little time for floor-wide restoration.
2. Only visible surfaces get wiped: under desks, chair legs and castors, the bottom edges of partitions and behind filing cabinets are usually missed.
3. General cleaners are not disinfectants: floor and glass cleaners make things look clean but are not designed for surfaces exposed to sewage.
4. No contact time: disinfectants need the dwell time the manufacturer specifies; wiping dry straight away may reduce their effect.
5. One cloth for everything: using the same cloth from toilet to meeting table can move germs around.
6. Masking odours with fragrance or air purifiers, while damp carpet and walls keep feeding mould.
7. Cleaning during working hours with chemicals is disruptive and can bother people sensitive to smells.

How WHD Office Disinfection Spraying Works in Lak Si

World Health Disinfection (WHD) is based in Bang Khae District, Bangkok 10160, and provides a disinfection spraying service by trained technicians. According to the service information, offices are among its listed customer types, alongside hospitals, schools, malls, airports, airlines, banks and residential buildings. Companies in Lak Si can book on 065-556-6294 or LINE @whd268. Dates depend on the schedule and same-day service is not promised, so contact WHD well before staff return.

Technicians use spraying and/or ULV (Ultra Low Volume) fogging. The disinfectant is CHEMGENE HLD4H, a medical-grade product from the UK containing Benzalkonium Chloride and Didecyldimethylammonium Chloride. The company's pages list approvals and references from Thailand's Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019.

Recommended steps for an office after flooding

1. Survey and plan. Send floor plans, photos and areas by LINE, noting where water entered, which rooms smell and the planned return date.
2. Remove mud and wash first. Areas water entered must be cleared, washed and cleaned. Wet, damaged boxes, carpets and materials should be removed and the space ventilated to dry.
3. Store items and protect equipment. Put important documents, food and personal items away, switch off and cover computers as technicians advise, and flag server rooms or sensitive equipment.
4. Zone and schedule. For example: lobby and reception, workspace, meeting rooms, pantry, toilets, document store and car park, usually done outside working hours such as Friday evening or the weekend.
5. Clear the zone. Staff and visitors stay out of any area being sprayed.
6. Technicians spray floors, carpet, desks, chairs, partitions, door handles, card readers, lift buttons, toilets, pantry and corners, using ULV in suitable enclosed spaces.
7. Wait before re-entry. The service information says about 30 minutes before normal use; always follow the technicians' timing on the day.
8. Follow up. Ventilate, check odour and damp, increase touch-point wiping and place hand gel at entrances and meeting rooms.

Communicating with staff

Tell employees before they return what has been done and when. A short email listing the areas cleaned and sprayed, the date of treatment, any surfaces that should be wiped before use, and a reminder that anyone feeling unwell should see a doctor and work from home does a great deal for confidence. Facilities teams in multi-tenant buildings should also coordinate with building management so that common areas such as lobbies, lifts and car parks are treated on a compatible schedule.

We do not claim spraying leaves no residue; ask the technicians whether food-contact surfaces in the pantry should be wiped before use. Customers receive a free CHEMGENE spray and WELLGIENIC wet wipes, and a tax invoice is available. If a document store or closed room still smells musty after cleaning, ozone treatment may be considered as an add-on.

10 Reasons Lak Si Companies Choose Professional Office Disinfection Spraying

1. Ready before return day, with work done outside office hours.
2. Floor-wide coverage, reaching under desks, behind cabinets and into corners more evenly than hand wiping.
3. Medical-grade disinfectant, CHEMGENE HLD4H from the UK, described on the disinfection service page.
4. Named organisms including COVID-19, RSV, influenza, norovirus, Salmonella and mould, matching workplace concerns.
5. Documented references from the Department of Medical Sciences, Mahidol University, NHS England and EN 14476.
6. Clear staff communication about when and where treatment happened, which supports morale.
7. Short re-entry time, about 30 minutes per the service information, following the technicians' instructions.
8. Lighter load on housekeeping and administration teams.
9. Supplies afterwards: CHEMGENE spray and WELLGIENIC wipes for desks and equipment.
10. Proper paperwork with a tax invoice; ask WHD on 065-556-6294.

Before and After: An Office After Street Flooding

Example Case: Preparing the Office Over a Weekend

This example case illustrates the workflow. It is not a report of an actual job for any specific company.

Imagine a Lak Si company with two office floors totalling about 800 square metres. Early in the week, the administration manager sends floor plans and photos to WHD on LINE @whd268. The team asks where water entered, which rooms smell and whether there is a server room, then proposes Saturday for the work and sends a quote for approval.

On Friday, staff lock away documents and personal items, IT covers equipment as advised, and housekeepers clear the pantry fridge and move wet boxes to a dry area. On Saturday, technicians start with the document store and car park where water entered, then toilets, pantry, meeting rooms and workspace, stating re-entry times as they go. On Sunday, housekeepers ventilate and wipe pantry counters again. On Monday morning the company emails staff listing the treated areas and asking anyone unwell to see a doctor and work from home. The business keeps running without losing a working day, and staff see that their health is taken seriously. A week later, the manager checks the document store again for odour or new mould spots and asks housekeepers to keep the extra touch-point wiping going until the end of the month.

Checklist Before and After Office Disinfection Spraying

Before spraying

• Check electrics and air conditioning in areas water reached before switching on.
• Clear mud, wash and clean car parks, storerooms and entrances where water entered.
• Remove wet, damaged carpet, boxes and materials; keep wet important documents separately in a dry area.
• Clear the pantry fridge and food.
• Lock away documents, personal items and small equipment; cover computers as advised.
• Inform staff, co-tenants or building management of dates, times and zones.

After spraying

• Re-enter at the time the technicians give and ventilate.
• Ask which surfaces to wipe again, such as pantry food-prep counters.
• Wipe card readers, lift buttons, door handles and meeting-room equipment more often during recovery.
• Place hand gel at entrances, meeting rooms and the pantry.
• Ask staff with fever, cough, diarrhoea or calf pain after wading to see a doctor and rest as advised.
• Track lingering odour or damp and report new mould.

FAQ: Office Disinfection Spraying After the Lak Si Flood

Q: Water never reached our office floor. Do we still need spraying?
A: Shoes and suitcase wheels can still carry contamination in, and respiratory viruses spread easily when everyone returns at once. Spraying touch points and shared areas adds confidence.

Q: How long must the office close?
A: It depends on size, but the service information says about 30 minutes per zone before normal use. Most companies schedule it outside working hours.

Q: What about computers and electrical equipment?
A: Switch off and cover them as the technicians advise, and flag server rooms or sensitive equipment in advance.

Q: Which organisms does the product cover?
A: WHD lists COVID-19, RSV, H1N1, H5N1, hand, foot and mouth virus, norovirus, Salmonella and mould. Others such as E. coli belong to the bacteria group the product says it covers. For specific test documents call 065-556-6294.

Q: We rent our office. Can we book directly?
A: Yes, for your leased space, while following building rules for contractor access. Common areas are building management's decision.

Q: How is the price set?
A: By area, condition and number of zones, quoted after photos or a site survey. A tax invoice is available.

Welcome Your Team Back to a Prepared Office

Ask about office disinfection spraying in Lak Si or anywhere in Bangkok. Send floor plans and photos for an initial assessment.

View WHD Disinfection Service

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

Related Links and References

• WHD disinfection spraying service: https://www.worldhealthdisinfection.com/en/disinfection-service
• CHEMGENE HLD4H disinfectant: CHEMGENE HLD4H product page
• Ozone disinfection for buildings: https://www.worldhealthdisinfection.com/en/residential-ozone-disinfection
• Thai PBS (26 Sep 2026), Ngam Wong Wan and Chaeng Watthana water levels: https://www.thaipbs.or.th/news/content/558585
• Thai PBS, flooding near Thung Song Hong Police Station: https://www.thaipbs.or.th/news/content/558575
• Thai PBS (27 Sep 2026), Vibhavadi Rangsit in front of Thai PBS: https://www.thaipbs.or.th/news/content/558662
• Thai PBS, Bangkok rainfall and disaster declaration: https://www.thaipbs.or.th/news/content/558661
• Naewna, Bangkok flooding points: https://www.naewna.com/n/bkk/81721/
• Bangkok Biz News, affected Bangkok households: https://www.bangkokbiznews.com/news/news-update/1255155
• Daily News, national summary 5 Oct 2026: https://www.dailynews.co.th/news/6249374/
• CDC Floods: https://www.cdc.gov/floods/