1. Microbial
Growth in
Homes
Presented by:
Bernard L. Fontaine, Jr., CIH, CSP
The Windsor Consulting Group, Inc.
14 Sheinfine Avenue,
South River, NJ 08882
Email: windsgroup@aol.com
TEL: (732) 221-5687

2. Microbial Growth in Homes
● Over a million species of fungi and bacteria
● Less than 10% microorganisms identified
● Fungi are multi-cellular – bacteria single cell
● Hyphae from fungi grow to form mycelium
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3. Microbial Growth in Homes
● Hyphae are vegetative or reproductive
● Vegetative hyphae get nutrients for fungus
● Reproduction may produce aerial hyphae
and spores
● Spores released from colony to disperse
fungus
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4. Microbial Growth in Homes
● Fungal growth depends on ambient
temperature, free water, nutrients, and time
● Fungi lack chlorophyll – get energy from
organic compounds
● Fungi excrete enzymes into food and digest
substrate and absorb water-soluble
compounds
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5. Microbial Growth in Homes
● Temperature: Range 0oC (cryophile) to 50oC
(thermophile) Most growth between 20-30 oC
● Water: Most fungi require free water but
Asp. species extract moisture from the air
● Nutrients: Minimal – organics with carbon
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6. Microbial Growth in Homes
● Time: Adequate moisture and nutrients at
suitable temperature
First few days: Produce vegetative hyphae
Once hyphae base established over 5-7
days then start spore production for fungus
flourish and spread
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7. Microbial Growth in Homes
● Fungi and/or bacteria comes from:
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Plants
Food
Soil
Air
Contaminated indoor/outdoor materials
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8. Microbial Growth in Homes
● Environmental Health Hazards:
◘ Irritation of eyes, nose, throat, and skin
◘ Infections – local or superficial (athlete’s
feet); local and deep (lung); or
invasive
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9. Microbial Growth in Homes
● Environmental Health Hazards:
◘ Infections – brain abscesses, corneal
ulcers, endocarditis, necrotizing
esophagitis, cysts, liver disease, meningitis,
peritonitis, pneumonia, sinusitis, and fatal
systemic diseases
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10. Microbial Growth in Homes
● Environmental Health Hazards:
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as
Allergies up to 20% of the US population
Most serious allergic problem is asthma
UK study showed wheezing in children
a predictor for fungal growth in the home
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11. Microbial Growth in Homes
● Environmental Health Hazards:
◘ Mycotoxins: Metabolites of fungi that can
have detrimental effects in humans
Often produced when nutrients limited
Affect immune system, blood, nervous system,
genetics, and some are human carcinogens
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12. Microbial Growth in Homes
● Environmental Health Hazards:
◘ Endotoxins: Metabolites of bacteria
causing detrimental
effects in humans
Fever, malaise, elevated white blood
cell count, respiratory distress, shock, and
possible death
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13. Microbial Growth in Homes
● Indoor Indicating Fungal Species
Alternaria sps.
Aureobasidium sps.
Cladosporium sps.
Trichoderma sps.
Aspergillus sps.
Chaetomium sps.
Penicillium sps.
Fusarium sps.
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14. Microbial Growth in Homes
● Common Outdoor Fungal Species
Ascospores
Botrytis sps.
Pithomyces sps.
Myxomycetes sps.
Basidiospores
Epicoccum sps.
Ulocladium sps.
Periconia sps.
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15. Microbial Growth in Homes
● Moisture Control Key to Prevent Microbial
Growth
◘ Check moisture content of lumber –
Wood is considered dry (<19% moisture)
◘ Cover building materials delivered onsite
◘ Seal framed house with plastic sheeting
◘ Insert driers to reduce moisture content
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16. Microbial Growth in Homes
● Moisture Control Key to Prevent Microbial
Growth
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Store building materials on pallets
Cover dirt with plastic sheeting
Cover exposed building materials
Schedule construction on drier days
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17. Microbial Growth in Homes
● Moisture Control Key to Prevent Microbial
Growth
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Fix leaks and seepage along foundation
Remove water from basement or slab
Keep windows and doors closed
Avoid condensation in HVAC ducts
Install dehumidifiers inside residence
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18. Microbial Growth in Homes
● Inspection Key to Prevent Microbial Growth
◘ Suppliers to inspect all building materials
◘ Cover loads delivered to construction site
◘ Framers and site construction managers
check lumber for visible fungal growth
◘ Report unsatisfactory building materials
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19. Microbial Growth in Homes
● Inspection Key to Prevent Microbial Growth
◘ Check flashing around windows and
doors, roof vents, and chimney
◘ Gutters drain water away from house
◘ Adequate ventilation in attic space
◘ Report water leaks immediately
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20. Microbial Growth in Homes
● Testing for Microbial Growth
◘ Inspect all building surfaces
◘ Air samples for fungal or bacterial
counts
◘ Surface samples for fungal spores
mycelial fragments, and mycotoxins
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21. Microbial Growth in Homes
● Testing for Microbial Growth
◘ Surface samples for bacteria and
endotoxins
◘ Air temperature and relative humidity
◘ Moisture measurements of affected
building substrates
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22. Microbial Growth in Homes
● Remediation for Microbial Growth
◘ Define work area and Level I-V
◘ Set up containment barriers, air locks,
and decontamination chambers
◘ Post warning signs for other trades and
emergency response personnel
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23. Microbial Growth in Homes
● Remediation for Microbial Growth
◘ Install air filtration devices and air movers
◘ Inspect containment for leaks
◘ Test airflow and static pressure inside the
containment barrier
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24. Microbial Growth in Homes
● Remediation for Microbial Growth
◘ Remove damaged building materials
◘ HEPA vacuum all affected building
substrates
◘ Damp wipe affected surfaces with a
biocide
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25. Microbial Growth in Homes
● Remediation for Microbial Growth
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Dry building substrates with dehumidifier
Apply antl-microbial coating
Inspect work for quality of workmanship
Clean work area, tools, and equipment
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26. Microbial Growth in Homes
● Post-Remediation for Microbial Growth
◘ Visually inspect all building surfaces for
visible microbial growth, dampness, and
containment of work area
◘ If acceptable, conduct air and surface
sampling inside/outside work area
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