Mold in Attics: How to Stop Mold Growth

A constant source of frustration in properties is with mold growth in attics, whether it be on rafters, on insulation or joists. One of the reasons this area is more inclined to mold growth than other areas of a property is because of the potential for high humidity in the area, as well as the lack of ventilation. There are also other considerations, such as roof leaks. 

To address the humidity issue, the area should be kept well ventilated. In a given area, relative humidity greater than 65% makes the area susceptible to mold growth. This is why inspectors tend to take measurements throughout the property with a hygrometer to deduce whether or not relative humidity is a contributing factor to potential mold growth in a property. Regarding ventilation, the rule of thumb in an attic space is that there should be 1 square foot of ventilation per 300 square feet of attic space. The type of ventilation required is dependent on the size of the space, the airflow in the area, the design and structure of the roof and the climate. It is best advised to consult with a roofing contractor if ventilation needs are not currently met in your property. 

The various types of ventilation that can be considered include the following: 

• Box vents: these types of vents don't have a mechanical mechanism installed and essentially just allow for air to rise out of the property. 

 

• Wind turbines: installed on top of the roof. Uses wind to suck heat/humidity out of the attic. 

 

• Power vents: exhausts heat from the attic. Generally work on a thermostat.

 

• Ridge vents: runs the length of the roof peak. 

 

• Soffit vents: generally installed on the underside part of the roof's eaves  

Other issues which can create mold issues in the attic include: 

• Insulation clogging between rafters, which hinders or thwarts air circulation around the soffit vents. 

 

• Unplanned ventilation areas due to gaps into the attic area due to openings around plumbing, or electrical boxes. 

 

• Improper exhaust vent ejection of air into attic. Exhaust vents should always be vented through the roof/soffit.

.
On top of mitigating against mold in the attic, enhancing the ventilation in your attic can also reduce energy costs in the winter time. Always consult with a licensed roofing contractor regarding ventilation systems in the attic. Always consider the potential for disturbing Asbestos containing materials when performing any work on a property built prior to 1980. 

If mold is discovered in the attic, it can be assessed by a mold inspector based on the source of mold, as well as tested using surface sampling. When mold is discovered in attics, air sampling is generally conducted directly below the attic access point. 


If you suspect you have a mold concern in your attic and would like a specialist assessment, CONTACT us here at Mold Mitigation Professionals and let us help you ease your concern. Providing mold inspection and mold testing services throughout Orange County and surrounding areas. 

Note: This information is not intended for personal installation or guidance. Further information and guidance on what will specifically work for your home and attic, always consult with a licensed professional and follow health and safety protocols.