Installing Copper Strips Under Shingles
Installing Copper Strips on a Shingle Roof
Think of how many people are out there who just had a new roof put on this past year. Not counting the one million new homes built last year I'll bet there were at least three million new asphalt shingle roofs installed on existing homes in the USA. The sad fact is that the wide majority of those new roofs have no protection against roof algae. The roofers or the homeowners simply are unaware of the problem and unaware that you can buy shingles that have copper coated colored granules.
I hope you are not in this situation. If so, no problem, as there is a way for you to poison those little devils, bacteriologically known as Gloeocapsa magma. We just need to clean your roof and then introduce copper onto your shingles. I know, you may not like the look of a 2 inch copper strip at the top of your roof. However, it will look a whole lot better than the unsightly algae stains!
Clean the Roof First
Common sense should tell you that you need to clean your roof first. That process is described in another article.
Getting the Copper or Zinc
Sheet copper or zinc is usually available at any roofing supply house. These are the places that REAL roofers go to purchase their roofing products. Do NOT confuse these places with the large home center stores sprouting up everywhere! The roofing supply houses sell copper for all kinds of roofing uses. They also sell zinc. Both metals will kill the algae, but I think you should use copper. Zinc has a tendency to produce a grayish film over time, so it may discolor your shingles. Copper should not cause a problem on your roof.
How Many Strips and Where?
That's tough for me to answer without seeing your individual roof. One thing is for sure, you need the strips as high up on the roof as possible, so that the copper coats as many shingles as possible. Depending upon how long your roof is, you may need a strip of copper halfway up the roof as well. Some roofs are big, some small. One strip, across the entire roof, having a 2 inch exposure should protect 14 to 18 feet of roof below it. This photo shows how the strip should look once installed. This strip is near the top of the roof and is tucked under the last fully exposed course of shingles. It is a piece of tin, not copper, and is only 20 inches long. I didn't have a strip of copper in stock at the time I took the photo. I just wanted to show you what it should look like. Your strips will run the entire width of the roof.
Installation of the Strips
Most asphalt shingles are installed so that they have a five inch area of the shingle exposed to the weather. You will also notice that you don't see any visible nails. If you lift up a shingle you should see the nails. They are just above the bottom edge of the shingle you just lifted. This means that you should be able to slide a piece of metal up underneath a shingle and not hit anything for about six inches (five inch exposure plus one inch nail height.)
Can you see how you should be able to slide a piece of metal up under a shingle for about six inches? At this point, it hits the nails holding that shingle in place.
Your task is simple. Cut long 7 to 8 inch wide strips of copper. Slide them up under the shingles until you hit the nails. Then, every four feet or so, lift a shingle tab and drive a copper nail through the copper strip. When you let the shingle tab back down, it should completely cover the nail. If this doesn't make sense, you had better call a professional roofer. I have seen lots of mistakes by homeowners with good intentions.