What is Zinc Roof Defense and how does it work?
What is it? Our Zinc Roof Defense is 99.9% pure zinc, it comes in a 4 inch wide roll and is simply rolled out along the roofs ridge line and applied with nails and adhesive to prevent the return of any stains caused by roof fungus below it.
Companies sell different width roof zinc, why? what is the difference? the width of the zinc greatly influences the protection the zinc can provide below. The rule of thumb when it comes to roof zinc is that for every 1 inch the zinc is wide it will protect 10 feet below. So the wider the zinc the better protection. Most residential roofs have a run from the ridge to the gutter span 18-28 ft. we made our zinc 4 inches wide to give every roof more than enough protection.
How does it work? The "theory" is that as it rains, the rain water washes millions of tiny microscopic metal ions from the zinc which flow down over the roof, coating the roof with zinc and prevents stains caused by fungus.
The effectiveness of the "metal ion" theory can be seen on most any stained roof, just take a look under any metal object on the roof, NOT aluminum objects like skylight flashing, but chimney lead, a metal venting pipe that sticks up out of the roof or best yet beneath a copper copula or weather vane, you should notice the area below it is free of roof stains.
The two photos below completely show the effectiveness of metal ions washing over a roof, the top picture is of a 20 year old roof, the metal ions from the copper cupola above the garage keep the roof clean all the way to the gutter. To the right, below the chimney the roof remains clean for about 10ft from the metal ions in the lead flashing around the chimney but lead bleeds very few active metal ions, therefore we always suggest applying Zinc Defense below chimneys. Copper and Zinc give off the most ionic protection of any metal that can be applied to the roof. The second photo down is an 11 year old roof that has a perfectly clean streak right below the copper cupola. These two photos are clear evidence of how effective zinc is, if you have the opportunity to apply zinc to your roof, we highly recommend it.
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Installation: Apply zinc to the first full course of shingles below the ridge cap from end to end and also below any obstruction like skylights. The Idea is to let the water run down over the zinc so do not tuck to much up under the shingles above it. It's best to butt the zinc up to the shingle above keeping most of it exposed. Each roll of roof zinc comes with 50 galvanized roof nails that have a rubber washer around the nail head to prevent leaks. Face nail the zinc every 2-4ft and also apply a construction adhesive like "Liquid Nails" behind the zinc to help ensure a permanent bond.
The photo below shows a recently cleaned roof that has had our Zinc Defense applied. Notice the strip that runs along the ridge line of the roof and the strips below the skylights, that is what correct application should look like, it looks uniform, it runs the ridge line and is below every roof obstruction.