A Story From the Field: An Old Riverside Warehouse Turned Gallery

Khun Ton owns a small art gallery inside a converted brick warehouse on the Thonburi bank of the Chao Phraya River, in Bangkok's Khlong San district. The building is several decades old. It has one main exhibition hall, a storage room at the back for works not on display, and a small corner set up as a private museum: old photographs, household objects and documents collected from the riverside community over many years.

During the October 2026 floods, the river pushed water into the building to about mid-shin height, and it stayed for several days. Khun Ton and his assistant managed to lift most of the paintings onto high racks in time. But some wooden crates holding prints and a stack of framed pieces in the storage room were still sitting on the floor when the water came in.

When the water receded, the first thing he noticed was the smell. It was a heavy, damp mustiness, much stronger than the usual rainy-season odor of an old riverside building. White salt lines had appeared on the plastered brick walls. The plywood display plinths had swollen at the base. In the corners of the storage room, grey-green mold spots had appeared on the walls and on the wooden crates. And most worrying of all, small mold spots were starting to show on the paper backing behind some of the frames.

Khun Ton wanted to act quickly, because an exhibition was due to open in a few weeks. At the same time, he was afraid that the wrong chemical or the wrong method could permanently damage works that could never be replaced. So his question was not simply "How do I remove mold?" It was "How do I remove mold from the rooms without harming the art?"

This article answers that question for private museums, galleries, artist-run spaces and collectors across Khlong San and the wider riverside area. The short answer is that the work has to be split into two clearly separated jobs, done by the right people, in the right order.

Why Museums and Galleries Need Extra Care After a Flood

• There is no second copy of an artwork: Paintings, prints, vintage photographs, documents and collected objects cannot simply be bought again. One wrong decision can destroy both sentimental and financial value. That is why speed must never come at the expense of method.
• Mold feeds on organic materials: Paper, canvas, glue, wood, leather and textiles are all food for mold. If the room stays damp and spores keep floating in the air, mold can spread from the walls to the frames and then to the stored works themselves.
• Visitor and staff health: Floodwater from the river and drains carries bacteria, including those that cause diarrhea, and the organisms associated with leptospirosis. Mold spores that grow afterwards can trigger allergies, asthma, sneezing and irritated eyes. Gallery visitors include children, older people and tourists walking the riverside neighborhood, all of whom deserve clean indoor air.
• Reputation and relationships: Visitors expect a calm, clean atmosphere in a gallery. A musty smell ruins the experience, and artists who lend or consign work may hesitate to exhibit again if they worry about the storage conditions.
• Insurance and documentation: If any works are insured, documenting their condition and choosing qualified specialists becomes essential. Photograph and record all damage before any work begins, both on the artworks and in the rooms.

The Most Important Principle: Separate the Two Jobs

For a museum or gallery, post-flood recovery divides into two parts that should never be mixed together.

Splitting the work this way means the artworks get correct specialist care, and the room they return to does not become the source of a second round of mold damage. It also makes it easier to explain the process to artists, lenders and insurers, because each party knows exactly who is responsible for what.

Why Common Quick Fixes Are Risky in a Gallery

• Pouring bleach around the room: Chlorine fumes can react with pigments, metals and paper nearby, and bleach stains walls and timber floors. It is not suitable for a building that houses art.
• Air freshener sprays: They mask odor temporarily, but some fragrance compounds can leave residues on surfaces, and none of them remove the mold that causes the smell.
• Powerful fans blowing across the room: If nothing has been disinfected yet, the airflow lifts spores off the walls and deposits them on any works still in the room.
• Returning works to storage as soon as the floor is dry: Brick walls and concrete floors keep releasing moisture for weeks. That moisture can bring mold straight back onto the works.
• Running ozone with the artworks still inside: Ozone is a strong oxidizer. It is excellent for destroying mold and odor in an empty room, but it should not come into direct contact with artworks, pigments, photographs or rubber materials. Works must always be removed first.

Hidden Mold Spots in Old Riverside Buildings

Old warehouses and shophouses along the river have their own weak points. These are the places the team checks first, because they are often missed during an ordinary clean-up.

• Thick plastered brick walls: They absorb a great deal of water and release it slowly. Even when the surface looks dry, the inside can remain damp for a long time, which is also what produces the white salt lines.
• Old timber floors and the void beneath them: Water and mud can stay trapped under the boards, creating an invisible source of musty odor.
• Behind false walls and hanging boards: The gap between a display board and the real wall is a classic place for mold to grow unseen.
• Wooden crates and cardboard boxes in storage: They soak up water and become ideal mold food. Replace them with new storage materials as your conservator advises.
• Air conditioning ducts and dehumidifiers that were flooded: If switched on without inspection and cleaning, they can blow spores straight back into the room.

The Solution: Disinfection Fogging and Controlled Ozone Treatment by WHD

World Health Disinfection (WHD) provides disinfection fogging and ozone treatment for flood-affected buildings. In galleries and museums, the team works only on the rooms and the building, and coordinates its timing with the conservator who is caring for the collection.

1. On-site survey: The team checks the flood line, the materials of the walls, floors and plinths, where the smell and mold are strongest, and confirms that every artwork has been removed from the areas to be treated.
2. Preparation advice: You get guidance on removing mud, taking out swollen materials such as damaged plywood plinths or gypsum boards, and cleaning surfaces before disinfection, since disinfectant works best on clean surfaces.
3. Disinfection fogging with Chemgene HLD4H: A fine-mist ULV fogger is used in rooms that contain no artworks, carrying the disinfectant into corners, brick joints, under shelving and throughout the storage room. CHEMGENE HLD4H disinfectant has no harsh smell.
4. Controlled ozone treatment: The empty room is sealed and an ozone generator runs at a dose and duration set for the room volume. This helps destroy mold spores and break down musty odor molecules in the air and on wall surfaces.
5. Ventilation: Doors, windows or the ventilation system are opened until the ozone has broken down, before anyone goes back in.
6. Re-check and planning the return: The team checks the smell and risk points again, recommends ongoing humidity control, and the works are brought back only when the conservator and the owner agree the room is ready.

Ozone safety: No people, pets or plants may be inside during treatment. Artworks, photographs, documents, rubber materials and sensitive electronics such as track lighting, display screens and humidity controllers must be removed or covered as the team instructs, and the room must be fully ventilated before re-entry.

For more on odor removal, see the ozone odor and chemical residue removal page.

A Recommended Sequence for Galleries After the Water Recedes

1. Photograph and document everything: the artworks, the rooms and the water line, for assessment and insurance purposes.
2. Contact a conservator: Ask them to assess wet or moldy works and advise on safe handling and temporary storage.
3. Move the works to a dry, well-ventilated space: Keep moldy works separate from clean ones so spores do not spread.
4. Clear and clean the building: Remove mud and swollen materials, then wash floors and walls.
5. Disinfection fogging and controlled ozone treatment in the empty rooms: carried out by the WHD team.
6. Keep humidity down: Run dehumidifiers and install humidity meters in the exhibition hall and storage room.
7. Bring the works back: only when the rooms are dry, the musty smell has gone and the conservator agrees it is safe.

This sequence prevents the most common and most painful mistake: carefully restored works being returned to a room that still harbors mold.

Planning Around an Upcoming Exhibition

Many galleries face the same pressure Khun Ton did: an exhibition date that cannot easily move. A few practical habits make that pressure easier to manage.

• Work backwards from the opening: Ask the conservator how long the works need, ask the treatment team how long the rooms need, and add time for humidity to settle before hanging.
• Prioritize the exhibition hall: If time is short, the hall where the show will hang can be treated first, with the storage room following.
• Talk to the artists early: Explain what happened, what the plan is and how their work is being protected. Transparency builds trust.
• Consider a temporary change of layout: If some plinths or walls cannot be replaced in time, a simpler layout may be better than rushing repairs that trap moisture.
• Keep monitoring after opening: Watch humidity readings and notice any musty smell after heavy rain during the exhibition period.

Understanding Humidity, Mold and Odor in a Collection Space

It helps to understand why mold behaves the way it does in a gallery, because that understanding shapes every decision that follows. Mold spores are present almost everywhere, all the time, in small numbers. They are usually harmless because they lack the one thing they need to grow: sustained moisture. A flood removes that limit overnight. Walls, floors, crates and the paper backing of frames suddenly hold far more water than normal, and the air inside a closed building becomes saturated.

Once spores begin to grow, they produce more spores and release the volatile compounds that we recognize as a musty smell. That smell is therefore not just unpleasant. It is a sign that something in the building is still actively growing. Masking it with fragrance hides the warning signal without removing the cause.

This is why a two-step approach works well for the rooms. Disinfection fogging deals with microorganisms on surfaces, including in places that cannot be reached by hand. Ozone treatment then works through the air of the sealed, empty room and helps break down both airborne spores and the odor molecules that have soaked into porous surfaces. Neither step replaces drying. Without long-term humidity control, any room can drift back toward the conditions that allowed mold to grow in the first place.

For collections, the practical lesson is simple: the room must be clean, disinfected and stable before the works return. A conservator can treat a print beautifully, but if it goes back into a storage room that still smells musty, the problem may simply start again.

A Simple Care Routine for the Months After Treatment

Recovery does not end on the day the rooms are treated. Old riverside buildings stay vulnerable through the rest of the rainy season, so a light but consistent routine makes a real difference.

• Read the humidity meters daily: Note the readings in a simple logbook for the exhibition hall and the storage room, and act early if they keep rising.
• Do a smell walk every morning: Before opening, walk through the building with fresh senses. A returning musty note is often the earliest sign of trouble.
• Check behind boards and in corners weekly: Shine a torch behind display boards, under shelves and into the storage room corners.
• Keep storage off the floor: Use shelving or pallets so that crates and boxes never sit directly on concrete again.
• Service air conditioning regularly: Clean filters and coils, and make sure condensate drains flow freely.
• Agree on a re-check point: Ask the team for a follow-up inspection if humidity stays high or the musty smell comes back after heavy rain.

These habits cost very little time, but together they protect both the building and the collection it holds.

10 Reasons Galleries and Private Museums Choose WHD

1. A clear scope of work: the team treats rooms and buildings and does not touch the artworks.
2. Willingness to coordinate timing with your conservator, so works return to a room that is truly ready.
3. Fine-mist disinfection fogging reaches brick joints, under shelving and deep into storage rooms.
4. Chemgene HLD4H has no harsh smell and leaves no lingering chemical odor in exhibition spaces.
5. Controlled ozone treatment, with dose and time set for each room, only after works have been removed.
6. Advice on covering or removing track lighting, screens and other electronics.
7. Help reducing the musty smell typical of old riverside buildings with damp brick walls.
8. Connected areas covered too, including restrooms, reception and the gift shop.
9. Humidity control advice after treatment to help stop mold from coming back.
10. Easy contact by phone and LINE, with quick initial assessment from photos.

Before and After: Khun Ton's Gallery

Customer Voice

"What reassured me was that the team said from the start that they would not touch the artworks. The conservator would look after the works, and they would get the rooms ready. Once the musty smell had gone and the humidity came down, I felt confident bringing the collection back."

— Khun Ton, gallery owner, Khlong San, Bangkok (illustrative scenario)

"As an artist with work in that storage room, I mostly wanted to know the plan. Hearing that the prints would go to a conservator and the room would be treated empty made it easy to say yes to the next show."

— An exhibiting artist (illustrative scenario)

Frequently Asked Questions

Q: Can ozone treatment be done with the artworks still in the room?
A: It is not recommended. Ozone is an oxidizer that may affect pigments, photographs and rubber. Always remove the works first and let a conservator care for them.

Q: Should I wipe the mold spots off a work myself?
A: No. Wiping can push spores deeper or damage the surface. Keep the work in a dry, ventilated place and have a conservator assess it.

Q: The old brick walls have white salt deposits. What should I do?
A: Salt lines come from moisture evaporating out of the wall. Let the wall keep drying, control humidity and disinfect the mold spots. If the wall is badly damaged, consult a builder experienced with historic buildings.

Q: Will the storage room need a second treatment?
A: It depends on humidity after the service. If the musty smell or mold returns, ask the team to re-check before putting works back into storage.

Q: Does track lighting have to be removed?
A: If it can be removed, remove it. If not, the team will advise on covering it and set the ozone dose accordingly. Any lighting that was submerged should be checked by an electrician before use.

Q: Do you recommend a particular conservator?
A: Choose a conservator experienced with the specific materials in your collection, such as paper, oil paintings or photographs. Museums, universities and professional conservation networks can often point you to qualified specialists. WHD focuses on the rooms and coordinates timing with whichever conservator you appoint.

Q: Can the small private museum corner be treated at the same time as the main hall?
A: Yes, as long as every object has been removed from that corner as well. Old photographs, documents and household objects are just as sensitive as paintings, so they should also be assessed by a conservator before they return.

Q: Is disinfection fogging safe for the building itself?
A: Chemgene HLD4H is applied as a fine mist on cleaned surfaces in empty rooms. If you have unusual historic finishes, mention them during the survey so the team can plan accordingly.

Q: How long will the gallery need to close?
A: It depends on the building size and how much clearing is needed. The team will estimate after the survey and plan to minimize the impact on your exhibition schedule.

Get the Rooms Ready Before the Art Comes Home

Galleries, private museums and creative spaces in Khlong San, Thonburi, Bang Rak, Samphanthawong and nearby areas can contact us for advice today.

Book Ozone Treatment – Click Here

See Disinfection Service – Click Here

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

Related Articles and Links

• Ozone odor and chemical residue removal
• Master Ozone Generator
• CHEMGENE HLD4H spray 750 ml
• All articles
• External source: WHO: Floods and health and Thailand Department of Health

#OzoneTreatment #MoldRemoval #OdorRemoval #PostFloodDisinfection #DisinfectionService #Disinfectant #GalleryFloodRecovery #BuildingFloodRecovery

Keywords: art gallery after flood, private museum flood recovery, gallery mold removal, controlled ozone treatment, post-flood disinfection, musty odor removal, Khlong San, Bangkok 2026