Does it kill existing fungi and mildew?
It will if it comes into contact. However, fungus spores can travel, and contact may be difficult if it has traveled to the interior of the wood. The mildew should be cleaned off first, and then the wood should dry completely before application of Termin-8. A wood preservative is designed as a preventative measure. Although existing problems can be helped or eliminated, there is no guarantee that it would stop those spores that have traveled microscopically and cannot now be treated by contact.
