Ventilation and Moisture Control

Mold – Is It Really a Problem?

A mold problem starts when there are conditions conducive in a home for mold spores to grow on. This condition is moisture levels over 20% and Relative humidity over 70% both present. Once conducive, mold can grow instantly! When mold begins growing in a home, the amount of air borne spores increases alongside its spread to other areas.

Although the issue of whether exposure to indoor fungi causes adverse health effects is controversial, there is no doubt that a severely mold-contaminated building can suffer structural damage, and that a foul-smelling, fungus-filled building is aesthetically unpleasing. Controversies about health effects aside, the latter two concerns are sufficient to merit a Complete Mold Inspection and remediation when an environment is found to have fungal contamination.

Preventing Mold Growth
Keep the building and furnishings dry. When things get wet, dry them quickly (within 24 to 48 hours). Perform routine cleaning, maintenance and repairs. The key to mold prevention is moisture control.

Furnace humidifiers must be cleaned regularly to prevent mold and bacterial growth

Humidifiers should be set to produce less than 60% relative humidity in the building. Relative humidity greater than 60% is likely to result in condensation in the building, and that can lead to mold growth

HVAC systems should be checked routinely because mold in a ventilation system may be spread throughout the building. Drain or condensate pans should also be checked regularly because they can become reservoirs for mold and bacteria if they are not installed and maintained properly. Filters for the HVAC system should be kept dry and should be changed frequently.

Fix leaky plumbing and any leaks in the building’s envelope as soon as possible.

Watch for condensation and wet spots. Fix the sources of moisture problems as soon as possible.

Prevent moisture due to condensation by increasing surface temperature or reducing the moisture level in the air (humidity). To increase surface temperature, insulate or increase air circulation. To reduce the moisture level in the air, repair leaks and increase ventilation (if outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).

Vent moisture-generating appliances, such as dryers, to the outside, where possible.

Maintain low indoor humidity, below 60% relative humidity (RH), and, ideally, between 30% and 50%, if possible.

Don’t let foundations stay wet. Provide drainage, and slope the ground away from the foundation.

If you are not experienced with home and building repairs, you may want to consult a professional when making necessary repairs, or for assistance related to mold-prevention changes to your home or building.

Testing for mold
Proper mold testing and investigation involves use of sampling pumps, tapes, swabs, cassettes and other tools by a qualified and trained personnel following a standard protocol as in Approved, sterile and supplied by the best labs in Canada specializing in mold bulk and air sampling.
Here at Acetech Home Inspections, our inspectors are trained and certified to test for mold and other indoor air pollutants like radon. See verification links below.

Mold verification

Radon verification

Fixing small mold issues

A mold problem less than 10 SQFT is considered a small mold mold problem. The key to permanently fixing any mold problem is determining and tackling the source of the moisture intrusion. Following which the affected area may be cleaned and treated with products designed to kill mold and fungi. Some options are plain white vinegar or bleach. Vinegar is very good at cleaning and killing mold on most surfaces. Bleach is an option however appears ineffective on porous surfaces like wood and drywall but works great on non-porous surfaces like tiles, plastic and metals.

Its A Bigger Problem. What Do I Do?
Mold problems over 10 SQFT is not generally considered a small mold problem. Also when the mold problem is hidden, this becomes much trickier to identify and fix. In both cases of a bigger or hidden mold problem, there may be a need for a mold mitigation and remediation company to assess and determine the best approach to eliminate the problem.


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