After a disaster, homes can be left contaminated with mold, bacteria, and other hazardous materials. Sanitizing homes is a crucial step in ensuring safe living conditions and preventing long-term health risks.
This page from the Disaster Response Development Coalition (DRDC) provides guidance on effective sanitization techniques, including mold removal, disinfecting surfaces, and restoring indoor air quality. By following best practices, responders can help communities rebuild safely and protect residents from post-disaster health concerns.
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Sanitation
Introduction
Sanitizing homes following a flood is a critical step in the disaster recovery process. Floodwater carries countless contaminants, including sewage, chemicals, and debris, everything nature and mankind have to offer, which can pose serious health risks to residents and volunteers and destroy homes. Proper sanitation helps to eliminate these hazards, ensuring that the home is safe for occupancy and preventing further damage.
One of the primary reasons for thorough sanitation is to prevent mold growth. Mold can begin to develop within 24-48 hours of water exposure and can spread rapidly if not addressed. Mold spores can cause respiratory issues, allergic reactions, and other health problems, particularly for individuals with compromised immune systems. By thoroughly cleaning and disinfecting all affected areas, you can significantly reduce the risk of mold growth and protect the health of the home's occupants.
Attention to detail is paramount when sanitizing a home after a flood. Every surface, nook, and cranny must be meticulously cleaned and disinfected to ensure that no contaminants are left behind. This includes walls, floors, ceilings, and any remaining furniture or belongings. Special care must be taken with porous materials, such as carpets and upholstered furniture, which may need to be discarded if they cannot be adequately sanitized. Due to this necessity for quality control, it is best for Team Leaders to focus on monitoring volunteers and handling the mixing of chemicals and filling of sprayers.
Glossary
Disinfectant : A chemical agent used to eliminate or reduce harmful microorganisms on surfaces.
Moisture Meter : A device used to measure the moisture content in materials, helping to identify areas that may be prone to mold growth.
Pump Sprayer : A tool used to apply disinfectants and cleaning solutions evenly over surfaces.
HEPA Filter : High Efficiency Particulate Air filter designed to trap very small particles, including mold spores and dust, improving air quality during cleanup.
Dehumidifier : An appliance that removes excess moisture from the air, helping to dry out damp spaces and prevent mold growth.
Personal Protective Equipment (PPE) : Clothing and gear, such as gloves, respirators, goggles, and coveralls, worn to minimize exposure to hazards during sanitation and remediation.
Respirator : A mask or device worn over the mouth and nose to protect against inhaling harmful substances, such as dust, mold spores, or chemical vapors.
Foundation Vents : Openings in a building’s foundation designed to allow air flow and ventilation, helping to dry out crawlspaces and prevent moisture buildup.
Shockwave™ : A commercial-grade disinfectant commonly used for mold remediation and sanitation after flooding.
Crawlspace : The area under a home between the ground and the first floor, often used for ventilation and access to plumbing or electrical systems.
Section 1: S.A.F.E.R.
Situational Hazards:
Poor Ventilation and Air Quality: Gutted homes often have limited ventilation, which can lead to poor air quality. This can result in the accumulation of dust, mold spores, and other airborne contaminants that pose respiratory risks. Using combination respirators can help protect against inhaling harmful particles and vapors,
Chemical Exposure: Sanitizing a home involves the use of strong disinfectants. These chemicals can be hazardous if inhaled or if they come into contact with the skin. It is essential to wear appropriate personal protective equipment (PPE) such as gloves, goggles, coveralls, and respirators to minimize exposure. Always follow the manufacturer's instructions for safe use and ensure proper ventilation when using these chemicals.
Extremely Slick Floors: Flooding and the use of cleaning agents can create extremely slick floors, increasing the risk of slips and falls. It is important to wear slip-resistant footwear and to be cautious when moving around the affected area. Placing absorbent mats or towels on the floor can help to reduce the risk of slipping.
Heat Exhaustion: Sanitizing a home can be physically demanding work, often carried out in hot and humid conditions while wearing PPE that interferes with our body’s natural mechanisms to regulate body temperature. This can increase the risk of heat exhaustion or heat stroke, which can cause symptoms such as dizziness, nausea, fatigue, coma, or even death. To prevent heat related illnesses, take regular breaks, stay hydrated, and wear lightweight, breathable clothing. If possible, work during the cooler parts of the day and use fans or air conditioning to keep the work area cool.
PPE
Chemical Resistant Gloves; Rubber or Nitrile
Combo Respirator
Goggles
Coveralls: Disposable, non-permeable
Boots: Waterproof are ideal
Section 2: Tools
Disinfectant
Moisture Meter
Pump Sprayer
Utility Vacuum with HEPA filter
Broom
Scrub Brushes: Stiff Bristle
Flat and Phillips head screwdriver
¼ in Nut driver
Razor Knife
Tin Snip
Hammer
Fan
Section 3: Walkthrough
Drying out the home
Place multiple fans under the home and open all foundation vents to ensure thorough airflow through crawlspaces, which helps to expedite the drying process.
Air out the home for several days by keeping windows open and using fans and floor blowers to promote maximum ventilation and moisture evaporation.
Upon completion of initial drying, close the windows and run dehumidifiers along with fans to continue reducing moisture levels. This step may take several days to achieve the desired dryness.
If central air conditioning (AC) is available and unaffected, use it to aid in dehumidifying the air inside the home after initial drying. Prevent contamination of the HVAC system during this phase by following these steps:
Replace the existing filter with a HEPA-rated filter.
Seal the seam between the filter and the frame using masking tape to prevent potential contamination.
Immediately replace the filter with a new one after the sanitation process is completed
Checking Moisture Levels:
Use a moisture meter to measure the moisture content of various materials in all rooms of the home, including walls, floors, and structural components.
Before treating wood for mold, ensure the moisture content is reduced to below 16%. Ideally, I aim for a moisture content between 12-15% to ensure successful sanitation as early as possible.
*NOTE In highly humid environments, treatment may be necessary at moisture levels as high as 19%. Under such conditions, delay reconstruction for at least 2 weeks following sanitation, and reapply sanitizer to the home prior to installing new materials.
Surface Preparation:
Brush, sweep, and vacuum dust and debris that has accumulated on since the initial cleanup phase.
Scrub all visibly moldy surfaces vigorously with a disinfectant using heavy-duty scrub brushes to remove mold spores and contaminants effectively.
Re-vacuum all scrubbed moldy areas.
*Scrubbing and re-vacuuming can be combined with the use of a stiff bristle vacuum hose tip
Applying Disinfectant:
Use a commercial-grade disinfectant, such as Shockwave™, for all exposed surfaces, including wall studs, joists, subfloors, and any other areas potentially contaminated by mold, including inside crawlspaces, basements and exposed attics.
IMPORTANT NOTE* Please note that Bleach and WILL NOT penetrate deeply enough into framing wood, sheathing, or other porous materials in a home to properly sanitize them and prevent future mold growth!
Use a garden or chemical sprayer for thorough applications and use a stiff bristle brush to scrub any areas where mold is visible, ensuring thorough coverage and penetration. When available the use of chemical fogger/fumigators is ideal for comprehensive sanitation.
Work methodically: Spray all surfaces of the home from top to bottom in a uniform manner completing each room of the home as you go.
* It is critical not to miss any areas during this process! Even the smallest of untreated spots can contaminate a home within its walls and destroy a home and health over years before showing on the surface.
All materials should remain visibly wet for a minimum of 5 minutes. Continuously monitor surfaces within a 5-minute application time behind yourself as you spray and reapply if a surface dries out or absorbs everything.
Scrub all surfaces that have visibly had mold growth vigorously.
Always follow the product's instructions for proper application, ventilation, and safety precautions to guarantee effective disinfection.
Air out the home:
After applying the disinfectant, use fans and dehumidifiers once again to accelerate the drying process. This step is crucial to ensure all surfaces are completely dry before proceeding with reconstruction.
The drying process may take between 48-96 hours, depending on the home's characteristics, outside environment, and equipment utilized.
Final Moisture Check:
Conduct a thorough moisture check with a moisture meter across all areas and materials in the home to confirm that they are sufficiently dry.
Moisture content below 14% in interior lumber is ideal prior to rebuilding.
Only after thoroughly verifying the dryness of the home should the residents be given the green light to proceed with reconstruction.
*Pro Tip: A quick but comprehensive “Knockdown Spray” can be of great help in reducing the growth of mold between when the home is gutted and can be sanitized. This is done by heavily spraying all surfaces of the home with disinfectant immediately following cleanup after gutting a home. This IS NOT equivalent to sanitation, and it is important to make the homeowner aware of this.
Homes re-built without proper sanitation can rot from the inside out and cause serious, sometimes deadly, health issues well before they show any indications on the surface.
*Pro Tip: When using fans and dehumidifiers during the drying process, position them strategically to circulate air throughout every room, including closets and crawl spaces. This ensures hidden damp spots don't get overlooked, minimizing the risk of mold regrowth.
*Pro Tip: Keep a detailed log of all cleaning, drying, and moisture checks, including dates, methods, and results. This documentation can be invaluable for insurance claims and helps track progress to confirm that all steps have been properly completed.
Restoring a home after severe damage requires careful attention to every step, from thorough cleaning and drying to meticulous moisture checks. Following these best practices not only helps prevent future issues like mold and rot, but also safeguards the health and safety of everyone involved. By documenting your efforts and prioritizing proper sanitation, you set the foundation for a successful and lasting reconstruction. Taking the time to ensure each phase is completed correctly will give homeowners peace of mind and help them move forward with confidence in their rebuilt space.