Expert: Michael J. Owen - 10/15/2009

Question
I would like to know the best solution for keeping mold out of a shake roof.  I would also like to have your opinion on a solar attic ventilator.

Thanks.

Answer
Hi Judy. I assume you mean keeping mold out of the attic space and not the outside of the roof?
In which case, adequate ventilation is the key. The rule of thumb is: 1 square foot of ventilation for every 150 square feet of attic space. Here is a web site that may help:

http://www.rd.com/18231/article18231.html

As far as Solar vents go, I have had no experience with them. However, I have heard that they are reasonably efficient providing there is sufficient air coming into the space from the soffit areas.
Hope this helps to answer your question.