In recent years, the issue of mold in buildings has increasingly attracted public attention. Even though mold has inhabited the planet for millions of years, it has only recently become a serious concern to many people, legitimate in some cases, exaggerated in others.

Mold is a type of fungus, commonly referred to as mildew whose spores, or seeds, are everywhere, both floating in the air and dusting all exposed surfaces. In North America, there are over 1,000 species of mold. Most molds do not affect humans and the majority of humans are not affected by any type of mold at all. So what has changed to make mold the major problem it has become?Mold

What we know today that we did not know before is that some people are affected by some molds in a number of ways including asthma, infection and sickness.

For mold to establish itself in a building, four conditions are required:

  • moisture
  • suitable temperature
  • organic material
  • mold spores

Mold will grow at locations which are periodically damp, such as inside a wall at a leak location, and will go dormant, but not die, during periods when the moisture level is too low to support growth.

Understanding Molds

  • Mold is a natural substance that is present everywhere.
  • Mold can be harmful or helpful, depending on where it grows.
  • Mold needs moisture to grow.
  • Mold does not grow on dry materials.
  • Mold growing inside a condo can affect the occupants.
  • Occupants can learn to recognize mold.

What Are Molds?

Molds are microscopic fungi, a group of organisms which also include mushrooms and yeasts. Fungi are highly adapted to grow and reproduce rapidly, producing spores in the process.

You encounter mold every day. Foods spoil because mold. Leaves decay and pieces of wood lying on the ground rot due to mold. That fuzzy black growth on wet window sills is mold. Paper of fabrics stored in a damp place get a musty smell that is due to the action of molds.

Molds can be useful to people. The drug penicillin is obtained from a specific type of mold. Some foods and beverages are made by the actions of molds. The good kinds of molds are selected and grown in a controlled fashion.

Molds are undesirable when they grow where we don’t want them, such as homes. Over 270 species of mold have been identified as living in Canadian homes. Molds that grow inside may be different from the ones found outdoors.

Toxic Mold

The term “toxic mold” is generally applied to large concentrations of the mold identified as “aspergillos/penicillum” or “Stachyborys”. It is not uncommon for it to appear as a dark slightly fuzzy or raised stain.

What Makes Molds Grow?

Molds will grow if we provide them with moisture and nutrients. If we keep things dry, molds do not grow. High moisture levels can be the result of water coming in from the outside, through walls or from plumbing leaks; or moisture produced by the people living in the condo, through daily activities like bathing, washing clothes or cooking or through the use of humidifier to add moisture to the air.  Moisture accumulates within a condo when there is not enough ventilation to expel that moisture.

Why are Molds a Concern?

Mold Investigation Damage to materials is one concern. Materials get stained or discoloured, and over time they are ruined. Moldy paper and cardboard disintegrate over time. Fabrics are damaged. When molds are growing inside the home, there may be a health concern as molds release chemicals and spores.

Health experts indicate, that depending on the type of mold present in a home the amount and degree of exposure, and the health condition of the occupant, the health effects of mold can range from being insignificant to causing allergic reactions and illness.

How Can you Tell if it is Mold?

Discolouration is a sign of mold. However, all discolouration is not due to mold. Carpeting near baseboards, for example, can be stained by outdoor pollution entering the home. Stains or soot may also be caused by the smoke from burning candles or cigarette.

Smell/Odour sometimes molds are hidden and cannot be seen. A musty or earthy smell often indicates the presence of molds.

Is There a Mold Problem?

Molds are always found in the air outside and in all buildings. They come into the unit in many ways, through open windows or doors, on clothing, pets, food or furniture. The problem starts when mold grows inside the unit. Some mold growing, for example on the window sill but not elsewhere, is not a cause of concern. You can clean the mold yourself. The presence of mold is a sign that there is too much moisture in your condo – a situation which must be corrected. Mold that is isolated inside walls and which cannot easily come in contact with the occupants is less of an immediate concern but should be dealt with by the Condominium Board.

How Much Mold is Growing?

Mold is considered to cover a “small area” if it is no longer than the size of a standard garbage bag folded in half (crosswise or lengthwise). If there is another mold patch beyond two garbage bag lengths away it is considered a separate patch (otherwise it all counts as a larger patch). Clean up small areas yourself using a detergent solution, household rubber gloves and a dust mask for protection. Small moldy areas may become larger over time if ignored, so it’s important to clean up and remove even small patches of mold. If the patch of mold is smaller than a 4 x 8 foot sheet of plywood or drywall, the mold area is considered “moderate”. You can clean up moderate amounts of mold but you must follow the proper procedures and use the proper protective equipment. A mold area is considered “extensive” if a single patch of mold is larger in area than a sheet of plywood. Do not attempt to clean up large areas of mold yourself.

Cleaning up Small Mold Areas and Preventing Mold Growth

Washable Surfaces

Scrub with a detergent solution, then sponge with a clean, wet rag and dry quickly.

Moldy Drywall

Clean the surface with a damp rag using baking soda or a bit of detergent. Do not allow the drywall to get too wet.

Mold that comes back after cleaning is usually an indication that a source of moisture has not been removed. Seek professional help.

Preventing Mold

  • Keep the condo dry.
  • Find and fix water leaks.
  • Discard clutter and excess stored materials.
  • Clean and maintain the condo regularly.
  • Encourage lifestyle practices that reduce moisture.

Basic Steps to Prevent and Reduce Mold Growth

  • Mold needs moisture to grow. Controlling the moisture and keeping the condo dry prevents the growth of mold.
  • Check your condo for signs of moisture and molds.
  • Find out if water is coming in from the outside and if substantial moisture is produced inside the condo.
  • Report any water leaks, moisture of molds to the Condominium Board promptly.
  • Think of the different ways moisture is produced inside the condo (for example, cooking, bathing, numerous indoor plants,humidifier unit). Remove the moisture as it is produced by using exhaust fans. In the absence of fans, open windows for a short time, but note that the wind can push the moisture to other parts of the unit.
  • Measure how much moisture is in the air. To find the relative humidity in your unit, you’ll need a hygrometer. You can buy one at a hardware store or electronics store. A hygrometer costs from $5 to $20. Relative humidity in the home should be between 30 and 50%.
  • Reduce the amount of stored materials, especially items that are no longer used. Molds can grow on fabrics, paper, wood and practically anything that collects dust and holds moisture.

Skypak Closet (HVAC Equipment)

  • Regularly clean the room and replace furnace filters.
  • If you notice molds or signs of dampness, such as water on your windows or wet spots elsewhere, do not humidify.

Laundry Areas

  • Use your clothes dryer exhaust at all times.
  • Remove lint every time you use the dryer.
  • Don’t hang-dry laundry indoors.
  • Dry your laundry tub and washing machine after you use them.


  • Turn the bathroom fan on when you shower. Keep it running for a few minutes after you finish your shower.Mold Carpet
  • Keep surfaces that get wet, such as the walls around the bathtub and shower, clean and dry.
  • If there is a carpet in your bathroom, remove it.
  • Check for water leaks under the vanity sink.
  • Keep drains in good shape by removing debris from them.

To Clean a Drain:

  1. Pour a handful of baking soda into it.
  2. Add a cup of vinegar.
  3. Put the plug in the drain.
  4. Let the vinegar and baking soda work for about 20 minutes.
  5. Run fresh water into the drain.
  6. If the drain is still clogged, use a small plumbing snake.


  • Use the exhaust fan over your stove.
  • Keep your drains in good shape. Follow the steps in the Bathroom section above.
  • There’s a drip pan at the back of your refrigerator. Pull the refrigerator out to clean the drip pan. At the same time, vacuum dust from the coils at the back of the refrigerator.
  • Check under the kitchen sink to make sure there are no leaks.

Closets and Bathrooms

  • Get rid of clothes and other stored items that you don’t use. Keeping your closets and bedrooms tidy makes it easier for air to circulate and harder for mold to grow.

Other Parts of the Unit

  • A dehumidifier helps to reduce moisture in he condo during the warmer months. Close the windows when the dehumidifier is running.
  • Vacuum often.
  • Clean hard floors with a damp mop.
  • Cut down the number of potted plants in the house. Soil is a good place for mold.

Does Cleaning stop the Mold Growth?

Mold will re-appear until its source of moisture is removed. High moisture levels that are not corrected can make the molds grow back quickly. Cleaning is only a temporary but essential measure.

Practical Approach

Air Sampling:

Air sampling is quite often used to confirm the existence and type of mold spores and their concentration. Samples should only be taken, if evidence of mold exists, and remediation of the contaminated area is complete. The samples provide a means of determining if the level of concentration of the various types of molds identified in the area of contamination have been reduced to an acceptable level.

Air sampling is not recommended where evidence of mold does not exist.

Interpreting the Results of Air Samples

The concentrations and composition of indoor airborne mold samples are compared with those of the outdoor samples. Generally, the total concentrations and types of mold found in the indoor air should be similar to those found in the outdoor air.

In general terms, the air sample results are evaluated to determine whether there may be an indoor airborne mold spore hazard.

  • The total airborne mold spore concentrations of the indoor air samples should be lower than the concentrations reported in the outdoor samples. If not, there may be an indoor source of mold contamination, and further investigation is required.
  • The concentrations of each type of mold found in each indoor air sample should be similar to or lower than the concentrations of the same types of mold in the outdoor samples. If not, there may be an indoor source of mold contamination, and further investigation is required.
  • There should not be any types of mold in the indoor air samples that are absent from the outdoor air samples. If there are, then there may be an indoor source of mold contamination, and further investigation is required.

You can help by making a conscious effort to:

  • Keep the unit dry. For obvious reasons water must be prevented from entering the condominium, but you can help by controlling moisture that is produced inside the condo.
  • Ensure that air circulates throughout your unit as the movement of air prevents the build up of moisture (condensation) on surfaces such as windows and exterior walls. (Opening window coverings to allow free movement of air over the surface of the windows reduces the risk of sever condensation)

To find out how we can help you with your next building engineering project or Reserve Fund Study in Ottawa, call us toll free at 1-888-348-8991.


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