How does mould grow?
Mould spores exist readily in nature and are an important
part of plants, soil and natural decay.
Mould needs food and water to grow. The food is any
cellulose material such as soil, wood, paper, organic debris,
dust, fabric, drywall, carpeting, etc. The water can come in
the form of high relative humidity, small water leak or flood.
If your relative humidity is too high or you have
condensation you could have a mould problem. If you have had a
water leak, roof leak, water appliance overflow, or flood you
have 24 hours to clean it up before mould begin to grow.
Why is mould growth a concern?
The difference between mould growth outdoors compared to
indoors is that outdoors there are a wide variety of mould types
(genus and species) that keep each other fairly balanced.
Indoor mould growth usually involves one or a few types of
mould species that greatly outnumber the concentration found
indoors even outdoors. Mould amplification indoors is usually
due to a moisture problem which will continue to fuel mould
growth. As time goes by the problem can become larger, more
severe and more difficult to clean up.
If the mould species found indoors is considered toxic or
pathogenic and in large enough numbers, then a variety of health
effects can occur.
Health effects can range from simple head aches, sinus or
breathing problems to more severe nose bleeds, skin rashes,
bleeding of the lungs, cancer, even death.
Why don't I just kill it with a
biocide or bleach?
Many products exist that claim to rid your home or office of
mould. What these products are not telling you is that a dead
mould spore is just as toxic or allergenic as a live mould
spore. The only difference is that it does not have the ability
to grow any more. You still have a mould problem! Mould needs
to be cleaned-up and removed from the indoor environment.
In many cases just as pesticides, the biocides used
(including bleach) can cause a whole other problem of indoor
environmental toxicity and pollution that is just as problematic
as the organism it is intended to kill.
If I find mould why don't I just
remove it and not bother testing it?
In some cases that is sufficient. However, you don't
necessarily need to see mould growth in order to have a
significant mould problem. Some moulds grow inside the wall
cavity without any evidence at all on the visible portion of the
wall.
In many instances mould may be visible in one room of a
building, but the source of the growth is in another room or
portion of the building which does not show visible evidence of
growth in readily accessible areas.
Some of our investigations have resulted in significant mould
growth findings where no mould growth was even suspected.
I found mould and have reduced the
relative humidity to 30% to dry it out.
Although high relative humidity can cause mould growth,
reducing the relative humidity to very low levels like 30% to
dry out the mould is not advisable either. Drying out the mould
can increase the chance of it aerosolizing. Mould has a natural
defense mechanism where if disturbed, attacked or is dying, it
will send out potentially millions of spores into the air that
will settle and grow elsewhere. Avoid high relative humidity,
but also avoid drying out. A relative humidity of 40% to 50%
would be more advisable and have the mould tested and removed.
I found mould growing in a corner of
my bedroom. I will just replace the drywall.
If you have mould growth you need to know
why and
how much. The source of the
mould should be identified in order to avoid the problem
repeating itself. If there is a roof leak or other moisture
problem it needs to be fixed.
A mould test should be performed to determine how bad the
mould problem is, what type of mould it is and if it's in any
other portion of the building. With this data a proper method
of removal can proceed. In some cases a carpenter can replace
the drywall. In other cases the unaffected portions of the
building, the occupants, and the people doing the mould
remediation need to be properly protected.
We just bought a house and will be
renovating. How can a mould test help.
Especially in scenarios where you don't really know the
history of the building, it is advisable to test for possible
mould amplification before removing walls, carpeting, or doing
another structural work. If you start removing drywall and see
the back side of it black with mould it is in many cases too
late.
Sick Building Syndrome or Building Related Illnesses are
increasingly the result of either careless building maintenance,
careless renovating practices, or toxic mould exposure caused by
aerosolized mould spores due to the removal of building
materials without proper mechanical safe guards. |
