Can Mold from a Roof Leak Increase Allergies?

Written by Trevor Leeds of Chandler's Roofing
Updated June 5, 2013
mold from a leak
Even a small leak can result in mold growth in your home's interior or attic.
Photo courtesy of DriRite

Learn how to prevent leaks and establish good attic ventilation to eliminate mold and lessen allergens in your home.

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Mold is a very common allergen, causing many of the typical allergy symptoms such as sneezing, congestion, runny nose or watery and itchy eyes. It could be invading your home through a leak in your roof. Mold can be a source of allergens, irritants and in some cases, potentially toxic substances such as mycotoxins, according to the Environmental Protection Agency. 

Though mold is common in the outdoors and not always a cause for alarm, inhaling or touching mold spores may cause allergic reactions in sensitive individuals, causing varying degrees of symptoms and even aggravating those with asthma.

How does mold grow indoors and what does it look like?

Mold needs moisture in order to grow and thrives in humid areas. Most mold problems in your home or office originate as a result of some kind of water intrusion, such as roof leaks, blocked rain gutters or plumbing issues. Gutters that are clogged can cause water to back up and seep into walls, fascia boards and even the roof deck.

Even worse is a prolonged roof leak, which allows moisture into your attic space and closer to your building’s main support rafters and air intakes. Combine this prolonged intrusion of moisture with an improperly ventilated and dark attic space, and it becomes a thriving environment for mold growth.

Often, we think of mold as the dark black, slimy substance we see on moist surfaces. This is the exterior sign of a problem. However, as mold grows, the mold's roots can penetrate deep inside wood, where it cannot be seen, thus weakening the structure over time and causing unnecessary and very costly lumber damage.

Steps to prevent mold in your attic and home

•  Clean rain gutters and unclog downspouts. Though this is a common DIY project, we strongly recommend having a professional check, seal and clean your gutters annually.

•  Repair roof leaks in a timely and effective manner with a licensed contractor. Roof tune-ups should be done annually.

•  Treat any lumber that could be harvesting mold with diluted bleach.

•  Ensure your attic has proper ventilation, both intake and exhaust.

•  Have your rooftop checked and cleaned of any mold growth.

•  Replace any lumber that has been structurally weakened by mold growth and wood rot.

•  Inspect and change the air filters on your A/C unit.

If in doubt, call a licensed roofing contractor to inspect your attic, eaves and rooftop, or a licensed plumbing contractor to inspect your pipes for signs of leaks and mold. It may just help your health this allergy season and save you lots of unnecessary damage in the future!

About this Experts Contributor: Trevor Leeds is the president of Chandler's Roofing, providing roofing services in San Pedro, Calif. Originally established in 1942, Chandler's Roofing has earned industry awards such as 2011 Roofing Contractor of the Year from Roofing Contractor Magazine, consecutive Angie's List Super Service Awards from 2010 to 2012, and Master Elite Roofing status with GAF, America's largest roofing product manufacturer. Follow him on Twitter or Google+.

As of June 4, 2013, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List.

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