The whole question of mould started as a simple nuisance in home maintenance but with experience and research has become a major element of creating and maintaining a healthy house. Of course, whenever research develops over time, recommendations change and things can get quite confusing.
Mould grows where there is constant moisture, warm temperatures and ideally something organic to feed on like wood, wallpaper glue or even the paper on drywall. Even if you clean-up mould, it will come back quickly if the moisture is still there to feed it. To avoid mould, or to prevent it from coming back after clean-up, you must control water leaks, control indoor humidity and find a way to warm up cold surfaces -- usually with either air sealing, insulation or air circulation. You need to avoid cold surfaces because they cause condensation, which is water, which grows mould. But let us concentrate here on cleaning.
One of the most common confusions is whether to use bleach or not to clean up household mould. You are right, bleach was recommended by everyone a few years ago, and in fact the standard formula was 8 parts water for 1 part straight laundry bleach. Today, bleach is not recommended in most cases of mould clean-up. Rather it is recommended to use unscented detergent and water, that's all. Why unscented? So that when it dries you can smell if there is still any mould that needs to be cleaned up, given that the human nose is incredibly skilled at detecting the presence of mould - that musty smell.
Bleach or other disinfectant may still need to be used if you are cleaning up a sewer back-up or a toilet overflow, something that has bacteriological contaminants in it. But bleach is now seen to be overkill for most needs, and dangerous to use.
Why is bleach dangerous? If you mix bleach with ammonia, it will produce a highly toxic gas - right in your face. Many household cleaners have bleach in them and many more have ammonia in them. That is why government bodies have become worried about suggesting that people mix bleach with anything. TSP is a good unscented cleaner, but if concentrated it is corrosive. Protect your skin and your eyes while working. Wear a mask as well to protect your lungs.
Why don't we need to kill the mould? For most of the mould in our houses, it is not the mould itself that bothers us, but by-products of the mould. Hence, dead mould can still raise havoc with allergies, because those by-products are not affected by the disinfectants. We have to clean-up and remove all traces of the mould. For more details on the three categories of mould (allergen, infectious, poisonous), as well as the debate between the spellings of mould and mold, see "Just What Is Mould Anyway?".
Today's recommendations also make a distinction between when simple cleaning procedures that you can do yourself are adequate, and when the problem is so big that you and your house need protection from the cleaning procedure itself. Spreading massive quantities of mould spores all around the house is not a good thing. Generally if all the mould together is smaller that a patch 3 feet by 3 feet, it is felt that you can tackle it yourself with some basic precautions. If you use a vacuum cleaner, you must use a special HEPA filter or you will just be spewing fungal spores all over the house. Simply scrape it up, wipe it up, and dispose of everything including your mask, gloves and double wash your clothes by themselves. When there is more mould than three feet by three feet, or it is deep inside the walls, call in a professional who is specifically trained to deal with mould, protect himself and protect your house at the same time.
The Canadian bible on cleaning up mould is published by the CMCH: Clean-up Procedures for Mold in Houses. The Canada Mortgage and Housing Corporation have also established a training and certification program for professional clean-up of mould. If you are interested in entering this field yourself, or are looking for someone in your area that is certified by the CMHC Residential Indoor Air Quality Investigator Program, call toll-free at 1-800-668-2642.