Well, had asphalt shingles installed to replace the Cedar shingles I had. I was especially sold on the algae resistant ones. So they were installed in August 2010. Last fall, I started noticing my shingles going green but paid no attention. This spring, I could not ignore it. I called the manufacturer and put in a claim, however, the manufacturer's claim has a question regarding how many square feet of shingles were used. I have called Dulai 4 times. It has been 2 weeks and I still have no reply. During one of the calls, I asked Mastan, from Dulai if he had any suggestions on how I could remedy the problem of the algae. I told him I had heard of products that you could put on the shingles. He did not recommend using any product because it would render my warranty useless. He finally suggested I go on my roof and clean it myself. He did stress that I would have to be very careful not to damage the shingles because I could render the warranty void. So, I asked if he had any company or person to recommend. He did not. So, I press on...still waiting to find out how many square feet of shingle was used for my roof.
I believe I wrote a glowing review about their installation of the shingles. However, I have my doubts about the product they advised me to use. I have sent my warranty claim....without the square footage. I will keep you tuned!!
UPDATE: Sept. 2013
Have continued calling with no success but a long list of excuses, including that removing shingles is impossible . I have found another Roofing company to take samples from roof.