How Does Humidity Affect Roofing Systems?

It goes without saying that factors like high speed winds, rain and UV radiation can impact a roof’s performance and service life. While not as noticeable as the aforementioned factors, changes in humidity levels can also affect your roof. In today’s post, Triangle Home Exteriors takes a look at how humidity can impact roofing systems.

Warping and Delaminating

Roofing systems are built using materials that can absorb moisture. The roof framing and decking, in particular, are made of timber and processed wood boards, respectively. These materials absorb moisture, which can result in swelling that can be compounded by thermal expansion. The problem with wood products is that cellulose saturated with moisture will not expand and contract evenly, resulting in warping and delaminating.

To counter the effects of exposure to humidity, the roof has to be made of treated wood to minimize moisture absorption. Moisture barriers and underlayment needs to be installed as close to seamless as possible. In case the roof is punctured, repairs need to be done as soon as possible to keep exposure to a minimum.

Moss and Algae Growth

Increased humidity levels can make the roofing surface favorable for moss and algae growth. A particular type of algae, Gloeocapsa magma or blue-green algae, is a hardy type of bacteria that thrives on such conditions, even with prolonged exposure to UV radiation. Blue-green algae can contribute to asphalt shingle decay and increase the roof’s dark-colored areas, which can result in increased heat absorption. 

There are various products that are formulated for blue-green algae removal, or, because copper has antibacterial properties, you can install copper strips at the ridges. If your roof is up for replacement, consider asphalt shingles laced with copper granules.

Corrosion on Metal Roofing

Galvanized sheet metal is vulnerable to corrosion when the bare metal is exposed to the elements. It is possible for corrosion to spread unnoticed if the affected area is hidden from view. To prevent corrosion, the homeowner must conduct regular roofing inspections and keep up with annual maintenance appointments. One may also consider choosing materials that do not corrode, like copper or stainless steel.

Our roofing contractors at Triangle Home Exteriors can help you protect your roof from the effects of high humidity and other outdoor conditions. Give us a call at (919) 615-1101, or fill out our contact form to schedule an appointment. We serve Cary, NC, and the surrounding communities.