Submitted by Lawrence Englehart, GPI Franchise Owner, Nova Scotia, Canada
Q. Can a home inspector tell me if there is mould in my attic?
A. First, let me clarify that the inspection for or the identification of mould is beyond the scope of a typical home inspection. Without getting too literal, whether we spell it as mold or mould, it is a type of fungus that will decompose organic material (e.g., wood, paper) and prefers damp or wet locations. Mould growth has been known to adversely affect people’s health and can cause wood rot and structural damage. Only an accredited mould professional has the necessary training and tools to accurately classify the specific mould species that may have invaded your attic space.
During the inspection of an attic, there are times when the home inspector will identify visible discolouration on the underside of the attic (roof) sheathing. There can be multiple reasons for the cause of this discolouration, but it is usually associated with excess humidity and poor ventilation in the attic space. Excess humidity can come from many sources, such as a bathroom fan or a clothes dryer venting into the attic space or exhausting directly into the soffit area; which, as a result of thermal convection, can cause the warm moist air to flow back into the attic.
Or another source might be from an uninsulated attic hatch or pull-down stairs or even gaps or other types of penetrations, such as pot lights, holes in the framing for plumbing, electrical or mechanical systems, etc. There are so many ways to improve ventilation in the attic, but each situation is different so it would be best to consult with a qualified attic ventilation specialist on possible solutions.
Regardless, the only precise way to know if you have mould in the attic is to have a mould professional take a sample (e.g., swabbing, tape lifting) from the discoloured area and grow it in a lab petri dish. This method would allow them to accurately identify the species of mould that is in the attic.
However, accurately knowing the species of mould does not change the fact that professional mould remediation will still be required. Ironically, it is not unusual for a mould remediation company to look into the attic space and say: “Yes, you have mould!”
If you do some research you will notice there are many companies that specialize in mould removal, control and remediation. Depending on the mould remediation company, part of the process usually involves addressing the causes of the mould growth by taking measures to properly ventilate the attic space and ensuring that visible gaps caused by any plumbing, electrical, or mechanical systems are properly sealed, as well as confirming the bathroom exhaust fan is venting directly to the exterior of the building envelope, etc. Depending on the circumstances, the affected area(s) may need to be removed or may require an application of a special antimicrobial disinfectant and followed up with a type of sealer/paint to encapsulate the area. It is not unusual for a severe mould infestation to leave black dust-like spores on top of the insulation, which will then have to be professionally removed and replaced.
If you still have questions or concerns, you should research online resources, such as Natural Resources Canada, CMHC or Health Canada. In the United States, visit your state department of health website or the Environmental Protection Agency website.
Tagged: attics, home inspection, home maintenance, Lawrence Englehart, mold, mould