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House Mold

House mold is not only unsightly but also a potential health hazard. People with allergies, asthma or other respiratory problems can have serious reactions to house mold spores. Also, molds produce digestive enzymes that help them utilize building materials as food. Therefore, apart from being a health hazard, house mold will also compromise the integrity of the materials it is growing on (see the picture on the right) such as wood, wallpaper, ceiling tiles, carpet, and baseboard.

White house mold growing from a basement ceiling
Photo courtesy of One Day Mold Removal

There are a number of factors that encourage house mold growth. By controlling these factors, we can subsequently control mold growth. The factors include: indoor humidity and moisture content of materials, temperature, air circulation, light, and the chemical composition of building materials. For an existing house we cannot change the chemical composition of building materials. Light and temperature would also not be practically possible to control in that we need light and warm temperatures in our houses. However, we can effectively control house mold by maintaining the levels of relative humidity indoors below 60% and also ensuring proper ventilation. Air circulation helps control moisture levels through evaporation.

What do you do if you see or suspect house mold growth?

If you see or suspect house mold growth do not panic. You may submit mold samples to a qualified mold laboratory to determine whether the mold present is hazardous or only a cosmetic concern. The MOLD TAPE SLIDE™ is a straightforward, inexpensive and effective method to sample visible mold found on any surface. From it you get information and guidance on what to do next. It is an easy way to determine if the mold is toxic and if it will require a professional to conduct more intensive investigation and remediation. Click MOLD TAPE SLIDE™ for details.

Peel off seal from slide to expose adhesive (see the words “Peel Here”)
Place sticky side of slide onto the surface with visible mold growth and press gently.

Place slide back into plastic snap-case.

 

If you can’t see mold growth but can smell “musty” or “earthy” odours you can also perform a preliminary air test (call 905-290-9101 for details) before calling in a professional.

Testing For Mold Growth In Residential Houses

Do you have or suspect mold growth in your house? A number of molds may be found growing in houses with damp, humid conditions. The mold can grow on anything from paper, wood, carpet, wallpaper, ceiling tiles, drywall, insulation material, cloth, leather, books to concrete. Some of these molds such as some species of Stachybotrys, Aspergillus and Penicillium are toxigenic (toxic molds). Others like Alternaria and Cladosporium are well known causes of allergic reactions in sensitized individuals.

The good news is that not all molds that occur in indoor environment are hazardous. However, any mold growth in a home should be treated as potential hazard. Current Canadian mold guidelines advise building occupants to clean-up and/or remove visible mold growth. Mold growth can be controlled by eliminating or reducing moisture on surfaces of materials susceptible to mold attack.

What are the indicators of possible mold growth?

  • Excess moisture or water damage. Excess moisture may result from leaks (from pipes or roof), flooding, standing water, condensation, moisture from cooking or washing, and rising damp. Signs of moisture problem may include warping, peeling out of paint, efflorescence, rusting of metal and dampness to the touch.
  • Discoloration of surfaces of building materials that are susceptible to mold attack. These discolorations could be due to mold growth or just water stains.
  • Earthy or musty odours. Earthy odours are an indication of microbial growth. Lack of moldy odours does not mean there is no mold growth. Not all molds produce detectable odours and inactive or dead mold may not produce significant odours.

If you see mold growth or discolorations, you may send tape samples to a mold laboratory to determine whether the mold present is hazardous or is only of cosmetic concern. Cleaning large areas of hazardous mold requires special protection. To take a sample of visible mold growth, no special mold testing kit is required! For details on how to take a sample of visible mold growth click Tape Samples.

If there is earthy or musty odours but no visible mold growth, you can test the air for mold. Air testing may reveal hidden mold growth. Generally, a professional would be required to perform air testing. However, for peace of mind, homeowners can perform preliminary air testing using a cost-effective and easy-to-use mold sampling kit, which will enable them to take samples in their own homes and send them to a laboratory for analysis. For details on air quality testing click Residential Air Quality Testing: How To Test Home Air Quality.

If you have questions regarding mold growth in your home, give us a call at 905-290-9101. We may be able to help you or direct you to the right professionals or resources.

Indoor Air Testing For Mould

There are a number of methods that can be used to test air for airborne mould spores and fragments. The method chosen would depend on the objective of the investigation and subsequently the type of data required. The following methods can be used for testing air for airborne mould contamination.

Settle Plate Method For Detecting Viable Airborne Mould Spores And Fragments
With this method, a set of plates containing suitable growth media is exposed at table‑top level for half-hour to 4 hours. The mould spores and fragments suspended in the air settle by gravity onto the growth media. Light particles that remain suspended in the air for many hours are likely to be missed out. However, it is the cheapest way of sampling air since no other equipment is needed.

Volumetric Air Sampling For Detecting Viable Airborne Mould Spores And Fragments
The settle plate method is generally not recommended. A better method involves impacting a known amount of air on some suitable growth media. The media could be liquid or solid. With this method viable spores or vegetative material would form visible colonies (referred to colony forming units) in the media. These are counted in the lab and expressed as colony forming units (CFU) per cubic meter of air.

Volumetric Air Sampling For Detecting Total Airborne Mould Spores And Fragments
One disadvantage of impacting air on growth media is that only the viable propagules can grow on the media and hence detected. It is estimated that only about 10-15% of the mould spores may be viable. To enable us have a better estimation of how contaminated the air is, air is drawn on onto some inert sticky stuff. Depending on the efficiency of the sampling equipment used most of the spores and other airborne particulate matter including insect parts, pollen grain, and all sorts of fibres are trapped onto the sticky surface. Since these samples are directly examined under a microscope, the analyst is able to count the spores and vegetative fragments and express them as spores per cubic meter of air. It is also possible to identify some of the spores to genus level.

For more information on mould sampling visit our web page http://www.moldbacteria.com/sendingsamples.html.

Mold Testing Methods

A number of mold testing methods are available for the detection of mold contamination in indoor environment. Testing can be performed on dust from carpet, floor, mattress, or other surfaces; bulk material such as pieces of drywall, carpet, ceiling tiles, wallpaper and wood. In some cases air testing may be necessary. When should one test for mold in dust, on bulk material or in air? The decision should be based on the objectives of the investigations being conducted. The objectives of the investigation should help determine the type of data required, that is, either qualitative or quantitative and subsequently the type of samples to collect and the method the lab should use.

For more details on mold testing visit http://www.moldbacteria.com/services.html

Providing Mould Facts And Mould Training

In an effort to provide quality information we have created 2 websites dedicated to providing unbiased information on mould and mould training. For mould facts, visit http://www.mouldfacts.ca and for mould training, visit http://www.moldtraining.ca.

More technical mould information may be found at http://www.moldbacteria.com and if you can’t find what you are looking for give us a call at (905)290-9101.

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