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MOLD
SOURCES |
All
mold needs to grow is the right climate and a food sources.
Oxygen-rich environments with humidity over 70% and temperatures above 60 degrees
Fahrenheit are ideal for mold growth, which happen to be also be ideal temperatures for human comfort.
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In the summer, when air-conditioning is in use, mold growth can
occur in and around vents and duct work in buildings. In the winter,
when buildings are heated, mold often grows in wall spaces between the
warm indoor air and the cold outdoor air. In either scenario, ideal
conditions for mold growth are inside exterior windows and walls where
one side of the wall is colder than the other, (especially uninsulated
closet walls along exterior walls), water vapor can condense on
building surfaces, just as it does on the outside of a glass of ice
water on a warm, humid day.
| OTHER
SOURCES OF MOLD |
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Flooding & Water leaks |
• HVAC Air Ducts |
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Sprinkler spray hitting the house |
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Overflow from sinks or sewers |
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Damp basement or crawl space |
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Steam from shower or cooking |
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Wet clothes drying indoors |
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Dark unventilated areas |
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• Swamp coolers |
• Humidifiers
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Following are some moisture problems that cause indoor mold growth:
Water Intrusion
Rainwater can enter a building through leaks in walls, windows or the roof. Surface or ground water may enter when there is poor foundation drainage. Flooding can, of course, cause catastrophic intrusion. In buildings that have slab construction, water can seep or wick up through the cement floor causing mold to grow on carpet pads or carpet backing. The building envelope (walls, windows, floors , roof , etc.) must be well maintained to prevent water from coming in, both to prevent mold growth and to maintain the structural integrity of the building.
Water Vapor
When relative humidity (a temperature-dependent measure of water vapor in air) becomes elevated indoors, building materials and furnishings absorb the moisture. Those damp materials can then provide a good place for mold to grow. If there are no cold condensing surfaces and the relative humidity (RH) is maintained below 60 percent indoors, there will not be enough water in those materials for mold to grow. However, if the RH stays above 70 percent indoors for extended periods of time, mold will almost certainly grow.
Damp Concrete
Wet or damp concrete slabs often contribute to indoor mold problems.
Concrete absorbs water like a sponge. Wet concrete in and of itself,
is not a problem. However, construction materials that are attached
to wet concrete, such as wood framing, wood flooring, carpet, pad,
tack strip, cabinets, etc., can all absorb the moisture from a
concrete slab, causing those materials to deteriorate over time and
establishing the ideal conditions and food sources for accelerated
mold growth.
How does concrete get wet? A number of ways:
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It never actually dried. Concrete is poured wet, but
often times, building contractors are under pressure to meet
deadlines and don't allow sufficient drying time for the
concrete before construction begins. The result is, the slab
stays wet for months, even years longer than it should have, and
in some case may never really dry out. In recent years some
builders have adopted minimum moisture requirements for concrete
before construction can begin, meaning they will not start
framing a structure until the concrete slab has reached a
specific moisture level.
- Insufficient
moisture barrier. Before indoor mold conditions became the
big issue it is today, little attention was paid to installing
moisture barriers under poured concrete slabs. Inadequate or
non-existent moisture barriers under concrete slabs is a serious
problem, especially in places like California where subterranean
conditions exist (meaning the land slopes toward the structure)
because rain and irrigation water flows to the slab, often
saturating the ground below.
- Improper irrigation and/or
drainage is a major contributor to excessive slab moisture.
A high percentage of the indoor mold problems we encounter are
the direct result of sprinklers hitting the house and saturating
the walls or foundation. As a rule, people tend to over-water
landscaping, and often times soaking shrubs, sod and flowers
that make contact with exterior walls. In other instances, the
landscape isn't necessarily over-watered, but the ground against
the building stays wet due to insufficient drainage.
- Plumbing issues.
This includes under-slab water supply lines that break or leak,
interior water supply lines to plumbing fixtures that break or
leak onto the slab, habitual water spillage from over-flowing
bath tubs and showers, dried out wax rings or improperly seated
toilets, leaking icemaker supply lines, hot water tanks,
dishwashers, washing machines, humidifiers, etc.
- Caulk and grout. Bath tub and shower grout and caulk
are things we don't often think about until we see mold growing.
By the it's already a problem. Regular maintenance of tub and
tile grout and caulking can't effectively reduce the potential
for bathroom mold, and in some instance eliminate it. It should
be noted that some builders do not seal tub and shower tile
work. Even if they do, sealing is not a once in a life time
event. Tub and shower tile work and tile floors should be
re-sealed once a year to prevent grout leaks and moisture from
seeping under tile.
How to tell if you have a wet
slab. The best way to acquire factual data about the
condition of your slab is to have it professionally tested. AMI
uses state-of-the-art electronic moisture detection equipment
that can provide you with specific details. There's also a
couple of visual tests you do on your own that won't provide
specific details but will indicate whether or not your slab is
wet.
1. Pull back the carpeting near an exterior wall and look
to see if the nails in the tack strip are rusty, or if the tack
strip itself shows any evidence of water stains, dry rot or
erosion.
2. Place a heavy item porous in nature on the slab and
leave it there for a few days. When you remove the item, check
to see if there is a wet stain outline on the concrete where the
item sat.
A positive answer to either of these two visual tests is a
strong indication of a wet concrete slab. Some indoor air
quality specialists do not agree that wet or damp concrete is a
cause of indoor mold problems. With all due respect to
"specialists", wet concrete slabs do contribute to moisture
problems in other porous construction materials, which when wet
can cause rotting, deterioration and a host of serious mold
problems.
NOTE: Most installers of hard-surface flooring such as
wood and tile will not guarantee adhesion of flooring materials
over concrete if the concrete exceeds moisture levels of 17%.
Plants
Plants, trees and flowers are known to cause mold and mold spores.
Also, watering indoor plants often causes mold problems,
particularly when water spills over onto flooring and walls.
Call us today to schedule an inspection. (800) 369-8532 |
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[mold
health effects]
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