First, a simple spelling problem. Is it 'mold' or 'mould'. According to the dictionaries, the two are equivalent, with 'mould' being primarily a British variation. But mold is active and dynamic, and dictionaries are slow in comparison. According to the Canada Mortgage and Housing Corporation, mold is the officially established international spelling to be used -- except that despite such official proclamations 'mould' is becoming more commonly used around the world. So those who establish such conventions are getting beat out by those who use the language, and even CMHC documents are showing up with 'mould' all over them... so to speak. Apparently 'mould' is in the process of winning the battle over 'mold'.
To confuse things completely, both terms also refer to a receptacle into which one pours a substance, such as plaster or Jell-O, to create forms. And then there is all of our crown molding! or was that crown moulding? that was probably molded plaster before someone carved it out of wood? or was that wood before the plaster?
Moulds are part of the fungi group of micro-organisms, which also include mushrooms and yeasts. They are familiar to most people as food spoilers on items such as bread or fruit. Moulds are in fact nature's decomposers in the food chain.
But back to our mold turning mouldy. What is 'mildew'? Actually both mould and mildew belong to the family of fungi, but mildew is the more restricted of the categories as it is generally used only to refer to a superficial fungal growth on the surfaces of plant leaves, which actually causes a plant disease. Technically, you will not find any 'mildew' on bathroom tiles or on drywall -- these are the domain of mould.
Mould has many faces. It will decompose organic material or can develop its own mass on inorganic material, such as on bathroom tiles. Above all, mould can grow rapidly -- under ideal conditions of moisture and temperature some forms of mould can double its mass in 24 hours.
ALERGIES -- INFECTIONS -- POISONS
There are three common categories of mould: those that can cause or aggravate allergies, those that can cause infections, and those that carry poisons. We can be thankful that of all the moulds found in nature, only some survive indoors. Those that cause infections or carry poisons will generally not bother us unless we eat them, such as on spoiled foods, and they don't generally grow indoors. When we are talking about indoor air quality, we are talking about breathing the spores from mould, and that pretty much limits our residential problems to allergies and other sensitivity reactions.
Interesting note: dead mould and live mould can have the same negative effects on our health because the components that bother us are primarily the by-products of the mould rather than the mould itself. A dead skunk still smells, and a dead snake is still poisonous. In practical terms, that means that just killing mould is not enough -- we want to carefully remove any mass of mould and clean it all off. For details about cleaning, check out 'About cleaning up Mould'.
THE LIMITS OF DISINFECTANTS
Second item of interest: disinfectants are just about useless with most indoor mould because infectious moulds are not the problem we generally face. We are troubled by left over traces that are not changed by disinfectants and bleaches. So the latest clean-up recommendations talk about water and unscented detergent as the primary clean-up agents. Unscented so that we can tell if the mould odour lingers after we think we have cleaned it all up, telling us there is more mould to be found. The exception to this would be if the mould was caused by a biologically contaminated flood, like a toilet overflow or a sewer back-up. Then you would use a disinfectant -- but CAUTION. Many household cleaners contain BLEACH and many contain AMMONIA. If you combine bleach and ammonia, you get a very toxic gas. One of the reasons government bodies have quit recommending using bleach is because of the fear that people will mix it into a cleaner containing ammonia.
WHY DIY MOULD TEST KITS ARE USELESS
Oh, one last thing. Mold spores exist all over and enter our homes every time we let in fresh air. You can't eliminate the presence of mold spores, so you can't avoid inhaling some with every breath. For most of us, our bodies are accustomed to this normal exposure and can deal with it, though some hyper-sensitive individuals have more difficulty than others. What we can do is eliminate the conditions inside our homes that allow molds to grow and develop concentrations of their irritants that affect everyone's health. Mold is not an all-or-nothing issue -- it is a question of reasonable control. In fact DIY mold test kits are not recommended -- simply because they will always test positive because there are always traces of mold spores in the air we breath, indoors and outdoors. These simplified test kits unnecessarily cause people to panic. Some well meaning, or not so well meaning, contractors will look at the results of an indoor air quality test and say that half the house has to be demolished, whereas the test may indicate no more impurities than if you took that same test in the garden outdoors. Air tests for mold can be useful when done by professionals who are trained to evaluate the signification of the results.
For many detailed articles on different aspects of mould formation, avoidance and clean-up, check the encyclopedia section of this web site for the keyword MOULD.