Molds are fungi that live in soil and in dead or decaying matter. Mold spores are found almost everywhere in the environment. They need moisture to germinate and take only a day or two to grow. While all indoor environments have some mold that comes in from outdoors, damp environments encourage mold growth indoors. For mold to grow, it needs water, oxygen, a warm temperature and something that contains carbon to feed on, such as dirt, wood and paper. Unresolved water incursion problems in schools can lead to extensive mold growth and potentially to health problems for building occupants.
Most molds are harmless, but some molds produce toxic substances called mycotoxins. Common health effects of mold exposure include allergic reactions (runny nose, congestion, irritated eyes), upper respiratory symptoms, cough, wheeze, breathing difficulties, new or worsening asthma, flu symptoms, fatigue, headaches, hypersensitivity and skin and mucous membrane irritation. Not everyone has the same symptoms, and some people are not bothered at all.
Moisture control is the key to reducing mold growth. Moisture problems in schools can be caused by flooding, poor drainage, misdirected sprinklers or leaky roofs, pipes, windows, foundations and other structural openings. They can also result from poor ventilation during regular maintenance activities like carpet cleaning or damp mopping of floors or from reduced use of air conditioning or heating during school breaks. High humidity can support the growth of mold once it has begun The following practices are known to be effective in reducing moisture problems and mold growth in school buildings:
- Maintain indoor air relative humidity below 60%
- Inspect for water damage and eliminate standing water
- Identify moisture sources and make necessary repairs
- Conduct follow up inspections to make sure leaks are completely stopped
- Do not install carpeting where there is constant moisture (drinking fountains, sinks, showers and pools) or on concrete slab
- Clean up spills or pools of water on smooth-surface flooring as soon as possible
- Clean and dry spills on carpets within 24 hours
- Clean and dry out wet building materials and furnishings within 24-48 hours. If completely soaked, materials such as ceiling tiles, wallboard or insulation often need to be removed and discarded by trained personnel using the proper personal protective equipment
- Make sure areas are well ventilated after cleaning of carpets or damp mopping of floors by opening windows, doors and using exhaust fans. Be careful not to over wet or soak carpet with liquid cleaning or rinse solutions so that the carpet can quickly dry and be back in service in just a few hours.
- Perform regular maintenance on heating, ventilating and air conditioning (HVAC) equipment. Keep HVAC drip pans clean, keep air flowing properly and do not block the airflow with furniture, books and papers.
- Do not let building foundations stay wet. Provide drainage and slope the ground away from the foundation. Cut back trees and shrubs that are touching the walls to allow sunlight and fresh air keep the building dry.
- For renovations and new construction, keep building materials dry and keep the site dry. Ensure that the building is designed to be easy to clean and keep dry.
QUESTIONS & ANSWERS:
Question: I think there is mold in my classroom at school. Should I ask for mold testing?
Answer: The best practice is to prevent mold from growing in the first place, not to test for it afterwards. The time and money spent on testing can be better spent on cleanup and repairs. If you suspect that mold is growing, the first thing that should be done is a visual inspection. Any mold found should be remediated according to federal or state guidelines. Testing done after remediation may be useful to verify that the repairs were effective and did not spread the mold beyond the contaminated area.
Mold air testing should not be done as a first step. It is time-consuming, expensive and often unreliable. There are no standardized protocols for mold testing and there are many unqualified individuals currently performing testing and analysis of mold samples. Thousands of substances, including mold, have no regulated exposure limits. There are no established standards or regulations to say what is hazardous to health and what is not. Testing is not necessary most of the time and it may not reveal mold in hidden areas and surfaces. If you see mold or smell mold, you have a problem. If you see water damage you may have mold in hidden places or it may develop within a few days.
Question: How do I read a mold report?
Answer: Mold is measured in Colony Forming Units (CFUs). The numbers are very large and not that important. Since there is no standard or regulated exposure limit for mold, we do not know how much or how little it takes to cause adverse health effects.
Laboratory reports of the analysis of air samples should compare the outside air with the inside air. The report should show a row for each mold tested for; a column for outside air and a separate column for each area where inside air was tested.
You have a problem if the lab discovers different types of mold inside than outside or different numbers (mold spore counts) inside than outside. The problem is not so much that mold is present, but that more mold is growing inside the structure than outside and/or that different molds are growing inside than outside.
Question: What are the signs that mold may be growing in my school building?
Answer: The signs of possible mold growth are the same as the signs of excessive moisture in the building. You should look for:
- Discolored or stained walls, ceilings or floors
- Standing water in refrigerator or air conditioner drip pans, or under plumbing
- Water droplets or signs of uncontrolled moisture on duct interiors and near humidifiers, cooling coils, or outdoor air intakes.
- Condensation forming around windows, pipes or indoor surfaces of exterior walls
- High humidity in locker rooms, bathrooms, kitchens and boiler rooms
If you see fuzzy, slimy or discolored surfaces, especially in damp or wet areas, it is probably mold. Molds are often green, black, purple or orange in color. An earthy or musty odor, or a smell like alcohol, is often a sign of hidden mold.
Question: How do I clean up the mold I found in my closet at school?
Answer: Do not use students to remove moldy materials and do not do it yourself!
Guidelines for safe removal of mold are available from federal or state environmental protection and health agencies. When investigating or cleaning up mold, trained personnel should wear protective equipment, including gloves, goggles and a mask or respirator. Clean up mold on hard surfaces with detergent and water and dry completely. Remove and properly dispose of any porous materials (wood, sheetrock, ceiling tiles, paper products) that have been significantly damaged by mold.
Question: What kind of mold or moisture problems have you found during a school walkthrough inspection?
Answer: Most of the mold/moisture problems that my Tools for Schools Team found during our walkthroughs had todo with unreported leaks and carpet spills. Another source of water damage we found came from aquariums and watering indoor plants. We also discovered attempts to address leaks cosmetically, either by continuously replacing ceiling tiles instead of fixing the leaky roof or by spray painting ceiling tiles to cover up water stains.
In one classroom, we found cardboard boxes filled with books and papers stored on a windowsill. The condensation from the windows was getting into the boxes and creating a moldy mess. In several other classrooms, we discovered that humidifiers brought in by teachers to make their rooms more comfortable were actually creating excessive moisture and causing mold growth.
We found several areas of hidden mold growth. The first involved a marker board placed against an outside wall. Moisture condensed on the cool wall behind the board, didn’t dry and resulted in mold growth. In the second case, a chalkboard installed over sheetrock had a loose chalk tray. When the chalkboard was washed, water got behind the board and mold grew. The third incident involved a drain pipe in a 100 year old building. The clay pipe drained water from the roof of the building into a basement drain and was hidden between closets in two adjacent classrooms. The pipe cracked and slowly leaked water into the two closets that were stuffed with cardboard boxes of teaching materials. The smell of mold finally alerted us to the problem.
EPA Mold website:
EPA Mold Resources website:
EPA Mold Remediation Guide
EPA Tools for Schools Kit Appendix H – Mold and Moisture:
EPA IAQ Design TfS Moisture Control:
EPA Molds and Asthma:
EPA A Brief Guide to Mold, Moisture and your Home:
EPA Building Air Quality: A Guide for Building Owners and Facility Managers Appendix C – Moisture, Mold and Mildew:
EPA A to Z Subject Index:
EPA Biological Pollutants Facts:
EPA Flood Cleanup: Avoiding Indoor Air Quality Problems
Centers for Disease Control Mold Resources:
CT DPH IAQ Testing Should not be the First Step:
CT DPH Remediation Guidelines for Mold Abatement Contractors:
CT DPH Mold Clean-up Guidance for Residences:
CT DPH IEQ website mold section:
Healthy Schools Network, Inc. Guide to Molds at School:
US Department of Labor OSHA A Brief Guide to Mold in the Workplace: