Can Ventilation Really Reduce Condensation and Mold Growth in an Attic?

Posted by in Apparent Mold/Biological Growth, Attic Ventilation, Roof, Wood | August 11, 2014

Most in the construction industry know that the attics of wood framed structures require adequate ventilation to reduce the risk of the condensation of excessive airborne moisture and the resulting mold growth.

But, how much does ventilation reduce condensation and reduce the risk of mold growth?

I think we can see from these photos that even a little free vent area can allow excessive airborne moisture to escape and allow the underside of the roof deck to remain relatively clear of mold growth in the vicinity of the venting through a static vent, a power vent, and even air leakage around a soil stack.

 

Roof deck relatively clear of mold growth around static vent.

V-1 Roof deck relatively clear of mold growth around static vent.

 

Roof deck relatively clear of mold growth around soil stack.

V-2 Roof deck relatively clear of mold growth around soil stack.

 

Unfortunately, the distribution of the vents and blockage of soffit vents at the eaves reduced the effectiveness of the ventilation throughout the remainder of the attic, which allowed condensation and mold growth elsewhere.

Reality again demonstrates the theory.

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