A Story from the Field: Two Houses, One Fence, and a Question Nobody Could Answer

Khun Aey is forty-two. She lives on the same plot of land as her parents in Sai Noi district, Nonthaburi. At the front, facing the road, is her parents' single-storey house, built more than thirty years ago. At the back is the two-storey house that Khun Aey and her husband built ten years ago, where they live with their two children, one in primary school and one in secondary school. The two houses share a front yard, a water storage tank, a water pump and an outdoor kitchen. Her father is seventy-three and diabetic. Her mother is seventy and has knee pain that makes stairs difficult.

During the October 2026 floods, water from the canal and the surrounding fields covered the whole plot almost to knee height and stayed for nearly three weeks. The family took her parents to stay with relatives in Nonthaburi town, while Khun Aey and her husband took turns coming back to check on the houses.

When the water finally receded, it was clear her parents' house had taken far more damage. As a single-storey house, every room had been flooded. Mattresses, wooden wardrobes, the sofa and the appliances had all been sitting in water. The old plaster walls carried water lines and black spots, and the musty smell was so heavy it was hard to stay inside for long. Her own house had a flooded ground floor too, but the upper floor was dry, apart from a musty smell that drifted up the stairs from the damp below.

Her parents wanted to go home as soon as possible; they felt they had imposed on their relatives for long enough. Her children needed to get back to school. Khun Aey was stuck on one question: which house should be cleaned first? If they started with her parents' house, the children could not come home. If they started with her own, her parents would have to wait even longer. And both money and helping hands were limited.

This article is for families in Sai Noi, Bang Bua Thong, Bang Yai and the orchard-house areas of Nonthaburi who have more than one house inside the same fence, and who need a sensible way to decide the order of recovery after a flood. The same thinking applies to any multi-generation household, whether the second building is a separate house, an annex, or a converted shophouse on the same lot.

Why Several Houses in One Compound Need a Different Plan

• The damage is not equal. A single-storey house is damaged throughout, while a two-storey house still has a usable upper floor. Treating them identically and simultaneously is rarely the best use of time or money.
• Family members have different vulnerabilities. Older people with chronic conditions and young children should be the first to sleep in a clean, dry room.
• Shared spaces link both houses. If the yard, water tank, pump and outdoor kitchen stay dirty, both houses keep receiving germs and odor.
• Ozone treatment needs scheduling. Nobody can be inside a house while it is being treated. If the houses are close together, windows and wind direction must be planned as well.
• Labor and budget are limited. A good sequence lets the family get back to normal life sooner, without waiting for everything to be finished at once.

In other words, the question is not simply "which house first?" but "which space can become safe fastest, and who needs it most?" Answering it that way usually makes the decision much less emotional.

The Risks a Family Has to Weigh

Older family members' health. People with diabetes may heal more slowly and pick up infections more easily. Wading through mud or walking on floors that are still slippery creates a risk of both wounds and falls. Mold spores and musty air can trigger coughing and allergies. Floodwater that has passed through fields and canals may carry organisms that cause diarrhea, as well as those associated with leptospirosis. Anyone who develops a fever, muscle pain or an inflamed wound should see a doctor. This article is not medical advice.

Children's health. Children often play on the floor, touch everything and put their hands in their mouths. Coming back to a house that has not been disinfected puts them at risk of diarrhea and skin rashes.

Family relationships. Not knowing when you can go home is stressful, and arguments come easily. A clear plan with a timetable reduces everyone's anxiety.

Cost. Doing everything at once without an order often means paying twice. For example, a house is disinfected, but the yard is still muddy, and dried mud dust gets walked straight back inside.

Why "A Bit Here, a Bit There" Usually Fails

• Switching between houses. One day you clean your parents' house, the next day your own, but neither is ever truly finished. Both stay damp and smelly.
• Using strong bleach in an older person's room. The fumes are hard on the lungs, and a floor wet with bleach is very slippery for someone who is unsteady on their feet.
• Painting over damp walls. The house looks new, but mold comes back under the paint within a few weeks.
• Forgetting the shared areas. The inside of the house is clean, but the water tank and pump still hold sediment, so the water used for washing dishes and bathing is not clean.
• Letting older relatives return while work is still going on. Dust, disinfectant mist and slippery floors are more dangerous than they look.

The underlying problem is that effort is spread thinly across everything, so nothing reaches the point where a vulnerable person can safely use it. Concentrating effort on one space at a time fixes that.

The Solution: Create a "Clean Base" First, Then Restore One House at a Time

The principle the World Health Disinfection (WHD) team recommends for several houses in one compound is simple: start with the space that can be made clean and safe the fastest, use it as a "clean base" for the most vulnerable people, and then work through the more heavily damaged areas. Each stage uses our disinfection service with CHEMGENE HLD4H applied through ULV fogging equipment, followed by ozone treatment to help reduce mold spores and musty odor.

The Recommended Order of Work

1. Survey the whole plot in a single day. We look at both houses, the yard, the water tank, the pump and the outdoor kitchen, note the level of damage, and ask that an electrician checks the wiring in both houses before the power is used.
2. Remove damaged items and shovel out mud everywhere at once. This step should cover the entire plot in one go, so mud from one spot is not tracked into another.
3. Clean base one: the upper floor of the children's house. Because it was not flooded, it can be made ready fastest. We fog the stairs and upstairs hallway, then ozone-treat the upstairs bedrooms to remove the musty smell caused by humidity. After ventilation, the children can sleep at home again.
4. The ground floor of the children's house and the shared areas. We disinfect the ground floor, the bathroom, the outdoor kitchen, the yard and the area around the water tank. The tank is cleaned and the pump checked by a technician. Once this stage is done, the whole children's house can serve as temporary accommodation for the parents, with a dry, clean ground-floor room set up for the mother who struggles with stairs.
5. Full treatment of the parents' house. After belongings are cleared and mud is washed out, the walls are left to dry for a period. Then every room is fogged, ozone-treated one at a time, and ventilated. Old plaster walls absorb a lot of water, so more than one check may be needed.
6. A final check before the parents move back. We check the odor, the walls and how slippery the floors are in the parents' house. When everything is ready, they move home, and we give advice on long-term humidity control.

Ozone safety: No people, pets or plants may be inside the house being ozone-treated. If people are staying in the other house, the team closes the windows facing each other, chooses a time when the wind is not blowing toward the occupied house, and ventilates fully before anyone goes back in. Sensitive electronics are removed or covered.

How to Talk It Through So the Whole Family Agrees on One Order

Explain the reasons in terms of safety. Many parents want to go back to their own house first. Explaining that a single-storey house damaged throughout takes much longer to dry, and that moving back while the walls are still damp is a health risk, helps them understand.

Make a visible calendar. Write the order of work on a large sheet of paper and put it up in the house. Show roughly when each stage will finish and who will move into which room. It cuts down on repeated questions and worry.

Involve older family members. Let your parents help decide which items to keep and which to throw away, especially things with memories attached, such as photographs or prayer books. It helps them feel that it is still their home.

Make the temporary room feel like home. When your parents move into your house for a while, bring their personal belongings, their medicines and their favorite pillow. It makes the adjustment much easier.

Agree on who decides on the day. On work days there are many small decisions to make quickly. Choosing one family member as the contact person for the team avoids confusion and conflicting instructions.

Checklist Before the Team Arrives

• Photograph the damage to each house separately, for relief applications or insurance claims.
• Make a list of who lives where, who is most vulnerable, and who needs to be back at school or work by which date, to help set the order.
• Have an electrician check the wiring in both houses before switching the power on.
• Throw away mattresses, sofas and chipboard furniture that were soaked, and check with the subdistrict administration or municipality about bulky waste collection.
• Pack your parents' medicines, important documents and valuables into sealed boxes.
• Arrange a temporary place for everyone, including pets, on ozone treatment days.
• Open the water tank to check for sediment, and do not use tank water for drinking or cooking until the tank has been cleaned.

Ongoing Care Once Everyone Is Home

Older single-storey concrete houses tend to stay damp longer than newer ones. For the first one to two months, open the windows of your parents' house every day, and check the lower walls, under cabinets and the corners of the bathroom once a week. Put anti-slip mats in the bathroom and in any area where mud used to sit. Wipe grab rails, door handles and the dining table regularly with a disinfectant spray.

Shared spaces such as the yard and outdoor kitchen work best with a joint cleaning roster: whoever uses them on a given day looks after them that day. If new black spots or a musty smell return in either house, contact the team early for a re-assessment. And do not forget the standing water in the garden around the houses; mosquitoes multiply very quickly in orchard-house areas after a flood.

It is also worth checking on your parents' routines in the first weeks back. Are they keeping windows closed because they feel cold? Are they storing things on the floor again? Gentle reminders, and small changes like a raised shelf or a fan placed to move air through the room, make a real difference to whether mold returns.

Variations: When Your Compound Looks Different

• Both houses are single-storey. Choose the house that was flooded for the shortest time or has the most tiled, non-porous surfaces as the clean base. One well-prepared room is better than two half-finished houses.
• The parents' house is the two-storey one. If your parents can manage stairs, their own upper floor can be the clean base. If not, set up a ground-floor room in whichever house dries first.
• There are three or more buildings. The same logic applies: one clean base, then the shared areas, then the remaining buildings in order of how quickly they can be made safe.
• Someone in the family is bedridden. The clean base must be completely finished, ventilated and checked before they move in, and their room should be the first to be prepared.
• A small shop or workshop is on the same plot. Treat it after the living spaces unless the family's income depends on reopening it quickly, in which case plan it as its own stage.

Whatever your compound looks like, the questions stay the same. Which space can be made safe soonest? Who in the family most needs a clean, dry room right now? Which shared areas connect the buildings and must be cleaned before anyone moves back? Once those three questions are answered honestly, the order of work usually becomes obvious, and the team can turn it into a practical schedule that fits around school days, work shifts and medical appointments. Writing the answers down together, as a family, also gives everyone a sense of control at a time when so much has felt out of their hands.

10 Reasons Multi-House Families Choose Our Service

1. One disinfection plan for the whole plot, not separate jobs in no particular order.
2. A clean base so older relatives and children can move in first.
3. Shared areas, the yard, outdoor kitchen and water tank surroundings are included in the plan.
4. It uses CHEMGENE HLD4H, suitable for surface disinfection in homes.
5. Ozone treatment helps reduce musty odor and mold spores in old plaster walls and furniture.
6. Ozone sessions are scheduled safely while family members stay in the other house.
7. The most damaged house is checked again before older relatives move back.
8. It reduces the cost of repeated work caused by a lack of order.
9. Long-term care advice, including our dust mite removal service for mattresses and sofas that are still usable.
10. Families can look after high-touch surfaces themselves with the CHEMGENE 750 ml spray.

Before and After: Two Houses in One Compound After the Water Recedes

What the Family Said

"At first we argued almost every day about which house to do first. The team came, looked at everything and explained that our upstairs should go first because it was quickest, and that my parents could stay with us while their house dried. Once we had the calendar on the wall, everyone calmed down. My parents are back in their own house now, and the musty smell is mostly gone."

Khun Aey, daughter and owner of the second house, Sai Noi (story from the field)

Frequently Asked Questions

1. Why not do the parents' house first, since they are the most vulnerable?
Because a heavily damaged house needs more time to dry. Preparing the space that can be ready soonest as a clean base gets older family members into a safe room faster, without waiting for their own house to dry completely.

2. What if the children's house is damaged more than the parents' house?
The same principle applies. Choose the space that can be made clean and dry most quickly as the base, whichever house it is in. The team will help you assess this during the on-site survey.

3. Can one house be ozone-treated while people are in the other?
Yes, if the houses are a reasonable distance apart. The team closes the facing windows, chooses a time when the wind is not blowing toward the occupied house, and controls the dose. The house being treated must have no people, pets or plants inside.

4. Do we need to clean the water storage tank too?
You should if floodwater reached the tank or the lid does not seal well, as sediment and germs may have got in. Clean the tank and have the pump checked before using the water for bathing or cooking.

5. What should older relatives with diabetes be especially careful about?
Avoid wading through mud or walking barefoot in areas that have not been cleaned, check the feet for wounds every day, and see a doctor about any wound or fever. This article is not medical advice.

6. Can both houses be done in one day?
Some of the fogging can be done in a single day, but a heavily damaged house usually needs its walls to dry before ozone treatment can be fully effective. Splitting the work into stages gives better results.

7. How long will the whole process take?
It depends on how long the water stood, the type of walls and the weather. The clean base can often be ready quickly, while an older single-storey house may need a longer drying period. The team gives a realistic timetable after the survey rather than a fixed promise.

Bring Every Generation Home to a Clean, Safe House

Talk to the World Health Disinfection team about sequencing disinfection and ozone treatment for the houses inside your fence.

See Disinfection Service - Click Here

Book Ozone Treatment - Click Here

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

Further Reading

• Residential ozone disinfection
• Ozone treatment for odors and chemical residue
• Dust mite removal service
• All articles
• External sources: WHO: Floods and health and Thailand Department of Health