Quick answer: After water and mould damage, work in this order: make it safe (electrics, structure, contaminated water), stop the water source, remove or clean affected materials (porous materials with mould or floodwater contamination are usually removed; hard surfaces can be cleaned), protect people during cleanup, then dry the building and verify with moisture readings. Dehumidifiers remove moisture from the air after the area is prepared; they don't remove mould. EPA guidance suggests professional help for mould covering more than about 10 square feet, for HVAC contamination, sewage, or where people have health concerns.
Quick answer
- Safety → source → clean/remove → protect → dry → verify.
- Porous materials with mould or floodwater usually go; hard surfaces can be cleaned.
- Call professionals for large areas (> about 10 ft²), HVAC, sewage or health concerns.
First response
- Keep people away from unsafe electrics, structural damage and contaminated water.
- Stop the leak if safe; photograph and map affected areas.
- Map where water reached: floors, wall cavities, insulation, HVAC.
Clean or remove?
| Material | Typical decision |
|---|---|
| Hard, non-porous (metal, glass, hard plastic, sealed concrete) | Clean and dry |
| Semi-porous (wood framing) | Clean, dry, assess |
| Porous (drywall, insulation, carpet, ceiling tiles) with mould or floodwater | Usually remove and replace |
| HVAC ducts with contamination | Professional assessment |
The CDC and EPA provide cleanup guidance (CDC, Mold cleanup; EPA, Flooded home).
Protect people during cleanup
- Gloves, eye protection and an N95 respirator for small mould cleanup.
- Contain the work area for larger jobs; ventilate safely.
- Keep vulnerable people out of the area.
Drying and verification
- Extract standing water; remove wet porous materials.
- Air movers plus dehumidifiers to dry structure and contents.
- Verify with moisture meters at marked points until materials meet the reinstatement criteria.
- Mould testing is rarely needed to decide cleanup; EPA explains when sampling helps (EPA, Mold testing or sampling).
See the commercial drying plan, dehumidifiers after leaks and drywall drying time.
Use a combination of air movers and dehumidifiers for drying after standing water extraction and removal of wet porous materials, with completion checked by material moisture readings.
When to hire a professional
| Situation | Why |
|---|---|
| Mould larger than about 10 ft² (about 1 m²) | Containment and protection needed |
| Sewage or floodwater | Contamination |
| Mould in HVAC | Spreads through the building |
| Hidden moisture in cavities | Needs instruments and opening up |
| Occupants with health concerns | Medical advice and careful containment |
| Insurance claims | Documentation |
Completion means
- The source is repaired.
- Contaminated materials are removed or cleaned.
- Materials are dry by measurement.
- Humidity is controlled afterwards (EPA recommends keeping indoor humidity below 60 %, ideally 30–50 %).
Our industrial dehumidifiers are used in large-area drying and humidity control after restoration.
FAQ
Frequently asked questions
Can a dehumidifier remove mould?
No; it controls moisture so mould doesn't grow back. Mould must be cleaned or removed.
When should I call a professional for mould?
For areas larger than about 10 ft², sewage, HVAC contamination, hidden moisture or health concerns.
How fast does mould grow after water damage?
It can start within 24–48 hours on wet materials; dry quickly.
Sources
- US EPA, Flooded home cleanup; Mold testing or sampling; Mold course.
- US CDC, Mold cleanup.
