Carl Powell
EHS Department – Ringling College of Art and Design

This training course will
acquaint you with why and
how mold forms in
buildings.

It will explore simple ways
to prevent and correctly
respond to water losses and
mold issues when they
occur.

The basic science of mold

Common causes of water intrusion and mold in
buildings

Water intrusion prevention practices

Responding to water intrusion issues

Mold investigations and remediation

Mold is a fungus, not a bacteria - they are very different organisms.

Fungi survive by absorbing nutrients from their immediate environment.

More than 100,000 identified species of
fungi exist in our environment.

Mold is a term used to classify a group
of microscopic fungi that grow in the
form of multi-cellular filaments called
hyphae.

Molds are ubiquitous (found
everywhere) in the environment, both
indoors and outdoors.

When a spore is released by its “flower” or “fruit”, called
sporangia, and finds a favorable place to grow, the spore will
“blossom” or germinate and begin to produce hyphae. As the
hyphae begin to grow, they branch out and interconnect,
forming a group called a mycelium.

The mycelium will continue to grow and spread across the
surface of the food source, be it bread or moist drywall. At
this point, most molds are visible to the naked eye, and can
be called a mold colony.

After the hyphae grow awhile, new spores or “seeds” will
form and be
released, those
spores will
germinate, and the
whole life cycle repeats again.

While molds are capable of growth in
just about any environment, they
are limited by one crucial factor,
moisture. When sufficient moisture
is present mold spores can germinate
and begin to grow in as little as 24 to
48 hours after becoming moist
enough.

While many mold spores require direct contact with water to
germinate, some molds only need elevated humidity to
grow.

The good news is if the water or humidity
problem is repaired and the moist or wet
building materials are dried quickly, mold
can be prevented quite easily. This is why
water intrusion issues must be treated as
an emergency and addressed quickly by
connecting the source of the moisture.

While moisture and water are the critical elements for mold
growth, it is the presence of cellulose-based food that really
causes it to thrive and spread.

Building materials that provide good
cellulose-based food sources include:
1. Drywall, regardless of the type of backing
2. Acoustical ceiling tile
3. Plywood, particle-board and oriented
strand board (OSB)
4. Loose fill insulation

Not all materials are “good food
sources”. But if dust, dirt or debris
become trapped in a material, such as
carpet or fiberglass insulation, mold
growth can occur.

With the addition of moisture, the dust,
dirt or debris can be an ample food
source and can result in mold growth.
Ventilation

While mold requires both food and
moisture to thrive, it does not require
good ventilation.

In fact, mold prefers areas where
ventilation is minimal such as inside wall
and ceiling cavities.
Trapped Moisture

Mold also grows below sub-floors and
behind any kind of vapor barrier,
including floor and wall coverings like
wallpaper. When water resistant wall
coverings are applied, especially along
exterior walls, it prevents the wall from
“breathing”. If this happens, moisture
becomes trapped between the drywall
system and the wall covering, and mold
can easily result.
Duration

The amount of time that moisture stays in contact with
building materials, their food source is another key mold
growth factor. The longer the duration, the greater the
likelihood that mold will grow.

This is why the slow leak that goes
unnoticed for sometime may be more
likely to result in mold growth than a
fl0oding situation where response is
more immediate.

Sources of water in a building can be both internal
and external.

Water intrusion events can occur
throughout all phases of the
construction process, after
construction is complete, and while
the building is occupied.
Internal
Internal sources of water can include…




Plumbing leaks
Sewer issues
HVAC issues
Humidity
Internal- Plumbing Leaks

This photo shows a plumbing
leak that went unnoticed and
unaddressed for some time
causing substantial damage.

Repair leaky plumbing, sewer leaks, sewer backups, and
HVAC leaks as soon as possible. This will save time and
money in the long run.
Internal- High Humidity

This photo is an example of how
excessive humidity promoted mold
growth on the surfaces of several
books. High humidity is often not as
obvious as a plumbing leak; however,
areas subjected to consistent high
humidity can become moist enough to
support mold growth.

Relative humidity above 60% will
readily support mold growth. Ideally,
indoor relative humidity levels should
be kept between 30 and 50% if possible.
External
Some of the most common external sources of moisture include:

Building envelope penetrations

Equipment exhaust vents

Negative building pressure

Issues with stucco

Landscape and getting grade problems

Flooding events
External – Building Envelope Penetrations

A building’s primary barrier for water
intrusion prevention is what is referred to as
its “ continuous building envelope”. The
greatest risks of water intrusion through the
continuous building envelope occur at
transition and integration points, such as at
windows / siding transitions (such as the
skylight depicted in this photo) as well as
plumbing points like hose bibbs and any other
penetrations or breaks in the “envelope”.
External – Building Envelope Penetrations

Ensuring appropriate and effective
sealing of transition and integration
points, both into and out of the
building envelope, will reduce water
intrusion or moisture buildup.
External – Equipment Exhaust Vents

Any vents that exhaust warm, moist air
from any mechanical equipment or
appliances should be a minimum of 12
inches off the ground to avoid buildup of
condensation on surrounding building
materials.
External – Negative Building Pressure

Negative building pressure results when an
HVAC system inside a building draws in more air
from the outside than it expels through the
supply ducts. A building either can be entirely
under negative pressure, or only have certain
zones of negative pressure.

When buildings operate under negative
pressure, some air must be introduced from
outside to balance the difference in pressure.
Ideally this air enters the HVAC unit through a
valve or duct and is dehumidified before being
introduced to the indoor environment .
External – Negative Building Pressure

Unfortunately, negative air pressurization
often results in air being sucked in around
doors and windows, through cracks in the
foundation, and through other penetrations
in the building envelope.

When this occurs, the outside air is not
dehumidified before entering the indoor
environment. Overtime, the indoor relative
humidity will increase, potentially causing
condensation and mold growth on cool
interior surfaces or inside walls.
External – Windows, Doors, and Roofing

One of the most common causes of
the water intrusion and air leakage is
from windows and doors. Leaking
windows and doors allow air and
moisture to enter the building. If the
problem is not properly diagnosed
and repaired, this can result in mold
growth, as well as deterioration of
building and finish materials.
External – Windows, Doors, and Roofing

Likewise, roofs are a major source of
water intrusion. The majority of roof
leaks occur in locations where a
continuous portion of the roof meets
the ridge or another intersecting
angle, wall or other penetrations.
Proper flashing at all these locations is
critical.
External – EIFS Issues

Exterior Insulation and
Finish System (EIFS) is a
building product that provides
exterior walls with an insulated
finished surface and
waterproofing in an integrated
composite material system.

EIFS is a lightweight synthetic wall cladding that includes
foam plastic insulation and thin synthetic coatings. It can
be considered the “shell” of a building. EIFS is not stucco.
Stucco

Traditional stucco,
otherwise known as
Portland Cement Plaster,
is a non- insulating material
used for cosmetic purposes,
not protection.

Since stucco is not meant to be a true moisture barrier, it is critical
to verify proper installation of the chosen exterior membrane prior
to applying stucco.
Exterior – Landscape Issues

Proper site grading and
drainage are important to
prevent moisture intrusion and
resulting mold growth in
buildings. If surface water is
directed towards the building or
trapped against the foundation
wall, moisture may enter the
structure, such as what
happened in the residential
building depicted in this photo.
Exterior – Landscape Issues
Intruding moisture may raise the relative humidity of the building, also
encouraging mold growth. Actions that can be taken to keep surface water
from affecting buildings include:

Installing well-maintained gutters with downspouts that discharge at least six
feet from the building foundation.

Grading the soil near the foundation to ensure the proper slope to direct water
away from the building.

Keeping vegetation away from the building perimeter.

Eliminating mulch or organic debris against the foundation walls, on the roof
or in the gutters that might trap and hold moisture.

Ensuring that the landscape irrigation system does not spray the building.
Exterior – Floods

Flooding events can occur during severe
weather such as hurricanes. As shown in
the photo, widespread damage and
fungal growth commonly occur after
these natural disasters.

The College’s Field Service Manager will
inspect the campus after a severe
weather event.
Prevention

Preventing water intrusions is
far simpler and less costly than
addressing water intrusion
problems and the potential
ensuring mold. Opportunities
to prevent water intrusion begin
during the design and project
planning process, occur
throughout the construction
phase, and continue throughout
the life of a building’s operation
and maintenance.
Prevention
Most of the construction – related errors
that can leave a building vulnerable to
water intrusion result from one or more
of the following issues:
 Improper installation
 Improper design and specifications
 Improper storage of building materials
 Improper job sequencing
Improper Installation

Incorrect installation of
moisture-control assemblies is a
frequent cause of water
intrusion. This photo depicts an
improperly flashed and
improperly sealed window.
Improper Design & Specifications

Another frequent culprit is improper
building design or component/
system specifications, including
simply selecting the wrong product
for moisture- sensitive applications.

This photo shows the improper use of
an exterior sheathing product in a
shower stall as the first line of
defense against moisture intrusion.
Improper Storage of Building Materials

This photo shows mold growth on
drywall that was not stored properly
on the jobsite, became wet, and was
subsequently installed and painted.
The drywall should have been
discarded, or thoroughly dried out
within 24 hours.
Lumberyard Mold

Lumberyard mold is the black staining
commonly seen on lumber during the
construction processes or on stacks of
lumber in lumber yards.

Although the black staining may be
visually unappealing, studies have
shown that they do not cause structural
damage to the lumber.
Improper Sequencing

Improper job sequencing often leads to
critical moisture-prevention
components being overlooked.

At the jobsite in this photo, the
bathroom tile was installed before the
water-proofing contractor could apply
the required liquid membrane product.
Prevention
The Operations & Maintenance (O&M)
plan should focus on careful maintenance
of the systems and assemblies most
commonly associated with water intrusion
issues, which include:

HVAC systems

Plumbing systems

Window and door assemblies

Roofing systems
Preventive Maintenance - HVAC Systems

HVAC systems are essential to keep
building occupants comfortable.
Unfortunately, they are also the primary
conduct and vehicle for the distribution
of airborne fungal spores present
anywhere in the building.
Preventive Maintenance - HVAC Systems

HVAC systems are especially favorable to
mold growth because they draw air
(usually loaded with fungi and moisture)
into a building where there are ample food
sources for mold to flourish. Fungal
growth within the HVAC system itself can
rapidly spread mold spores throughout
the entire zone or building. Therefore, any
visible fungal growth found in any
operational HVAC system needs to be
addressed immediately.
Preventive Maintenance – HVAC Systems

HVAC systems can be complex, and a
properly designed system takes into
account space utilization, number of
occupants, and square footage. All airhandling units should be operating
properly and protected from outside
elements including pollutants and birds.

To ensure a HVAC system is in
compliance, it should be evaluated
against the American Society of Heating,
Refrigerating, and Air – Conditioning
Engineers (ASHRAE) Standards.
Preventive Maintenance – Plumbing Systems

Because plumbing leaks are so common,
all accessible plumbing components
such as pipes, fitting, and valves, should
be inspected regularly for signs of
leaking, corrosion, or other evidence of
water intrusion. Exterior plumbing
assemblies such as irrigation systems,
fountains, pools, and exposed pipes
should also be routinely inspected and
tested.

If evidence of leaking is found, take
immediate action to address the water
issue before mold develops.
Preventive Maintenance – Windows &
Doors

All interior and exterior wall systems and
finishes should be inspected regularly for
signs of water intrusion. Pay special attention
to windows and doors and all related
components to ensure they are in good
condition and working properly.

Any suspect conditions such as warping,
bubbling, or staining as shown in the photo
should be noted and promptly investigated.
If water intrusion sources are identified, the
causes should be successfully repaired and
the damaged components should be either
cosmetically repaired or removed and
replaced.
Preventive Maintenance - Exterior Trim &
Siding

Wood trim, window frame connections and
exterior fixtures should be periodically inspected,
caulked and painted, as needed. Exterior
Insulation and Finish System (EIFS) should be
carefully inspected to ensure penetrations and
gaps are not in contact with the soil or
vegetation. Verify drainage EIFS are functioning
property.

Properly seal any entry points to prevent water
intrusion. In the case of stucco, cracks less than
1/8” should be patched using a compatible
caulking. Cracks greater than 1/8” should be
investigated to determine the cause and an
appropriate repair should be made.
Preventive Maintenance – Roofing Systems

Roofing products have a service life and
should not be used beyond that point.
Service life may be reduced by weather
conditions, building design, and
maintenance.

At a minimum, roof covers should be
inspected by knowledgeable maintenance
personnel, or a qualified inspection firm,
one year after re-placement and every
year thereafter.
The most important steps to take in
response to a water intrusion/water
loss are:
 Shut off the water, if possible
 Secure the safety of all occupants
 Identify and repair the cause or
source of water
 Determine if visible mold is present
If visible mold is present:

Notify the Field Services Manager to initiate the Water
Response and Mold Prevention Program.

If the affected area is small (<10 sq. ft), maintenance
personnel may perform the dry out and clean up
procedure.

If the area is greater than 10 sq. ft, a subcontractor will
need to be contracted.
Recognizing the presence of mold is not always obvious, especially when you
can’t see it. The following situations or conditions may indicate that hidden
mold is present:

Musty or damp odors are noticeable in the area

Building conditions favorable to mold growth are
present, such as condensation and high humidity

Porous or semi-porous building materials, especially
cellulose-based materials, are noticeably moist or
wet in the area of concern

Building materials in the impacted area have been
wet for 24 to 48 hours or more

Evidence of previous moisture problems such as
staining, cracking, and warping is observed
Additional situations or conditions that may
indicate that there is a hidden mold problem
include:

Relative humidity levels in the building have
been greater than 60% for extended periods

The HVAC filters or flex duct have become wet

Proper maintenance is lacking

Occupants have complained about indoor air
quality, odors, and health symptoms

Water intrusion or mold problems have
previously occurred in the same areas
Water Staining

Water staining is not mold. However,
water staining can indicate a leak or
water intrusion has occurred. Since
moisture is the critical element for
mold growth, the staining may be a
precursor, particularly in unventilated
areas that are not visually assessable.
If mold is observed or suspected, it is important to investigate and
remediate the situation in an appropriate manner. However, it is
important that you:

DO NOT open up wall cavities or concealed areas where mold may
be growing without first containing the area.

DO NOT use fans or other “air moving” devices in the affected
areas.

DO NOT remove impacted items before containment area(s) are
established. HVAC vents are sealed (if possible) and personal
protection is worn.

DO NOT remove building materials that may contain asbestos or
lead paint without an assessment and testing.
Not every water intrusion or loss results in mold nor do they require
elaborate precautionary actions. Facilities personnel can perform water
intrusion clean-up work provided that the following are true:

Only clean water was involved

No visible mold is present

The source of the moisture has been
identified and fixed

The event is less than 24 hours old

The impacted area is clearly delineated
and clean up efforts are limited
If any of these conditions are not true, it may be necessary to bring in
a qualified environment consultant to assist.
Microbial investigations often consist
of the following tasks:

Visual inspection

Moisture measurements of building
materials

Sampling or testing (air, bulk,
surface)

Use of other specialized equipment
such as infrared imaging cameras,
bore scopes, etc.
Although over 100,000 species of molds have been identified, if its generally
not necessary to conduct pre-remedial sampling to identify the type of mold
encountered.

For the most part, if you see mold, it should be
removed either by cleaning or physical removal.

Removal procedures generally will not vary based
on the type of fungi.

Basically if the cause of water loss and extent of
damage are known, and there are no health
complaints, it is usually best to perform
remediation first.
Not sure if what you are seeing is mold?

There are occasions when testing is
necessary.

For instance, when it is unclear whether
the visible bioorganic growth or
discoloration you are seeing is indeed
mold.
If mold testing is deemed necessary, you will need assistance of a
qualified environmental consultant.

It is not advisable to perform in-house testing using
Do-It-Yourself (DIY) mold test kits, such as those
commercially available at popular hardware stores.

These test kits will only tell you that mold spores are
present in the air, which is no surprise since molds ARE
everywhere.

In short, if you need any sort of testing to asses a mold
situation, turn to the professionals.
A subcontractor will be contacted if:

If the area is greater than 10 sq. ft.
or

If gray (contaminated with chemicals)
or black water (contaminated with
sewage) is involved.

Biocides or antimicrobial chemicals should
never be used as a substitute for the removal
of mold and mold spores.

Removal is the key to mold remediation,
either by wiping away the mold or by
physically removing the impacted materials.
In wiping away mold, it is only necessary to
use a solution of water and soap or a mild
detergent. Biocides or other antimicrobial
chemicals are not needed in most situations.

It is important to remember that dead mold
spores can be just as unsightly and
problematic as live mold spores.
All water losses or mold
contaminations must be documented
via the paperwork in the Water
Response and Mold Prevention Plan.
Report all water losses or mold
contaminations to the Field Services
Manager.
The Field Services Manager will
oversee the process.
• You have completed the training.
• Now take the quiz - available at
www.ehs.ringling.edu
under training – Mold Awareness.
• Use this presentation to assist you.