Stones Falling Off

Hi. We installed 4.5 years ago a aluminum-zinc stone-coated metal roof. We live in the Philippines with very hot and very wet seasons. Our house is not sheltered by any big trees/covering. This year, after the hot summer (June 2015), we noticed that stones from the roof were sloughing off. It was particularly bad when it rained. We've collected about 3kilos of the stones and for many panels, the metal underneath can already be seen. Do you have any experience of this problem? Is it related to algae? The NZ manufacturer claims that the algae causes stone loss. We believe otherwise. We believe that the issue is the acrylic adhesive that binds the stone to the metal panel. During summer, the temperature is at an average of 36deg C/97deg F; it goes up as high as 100deg F for several days. Can the extreme heat weaken the acrylic adhesive? Would appreciate your professional comments.		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20632/find/
Can you possibly send me photos of what is happening? How bad is the roof algae?		Todd Miller Isaiah Industries, Inc. 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20633/find/
Surely. Based on a sample taken from the roof, the NZ manufacturer tested it and said that the panel is covered with black algae. BTW, failed to mention that the color does not seem affected The color of our roofing is still nice and even - except where the metal sheet is exposed. Also, please note that the ending caps flush to the fascia boards have no stone loss. Only the panels that are exposed to the sun. I have more pics to send - how do I do that here?		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20634/find/
Here is another pic.- Close-Up of Valley		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20635/find/
Here's pic #3 - The roof panels - #5 from the top is different in color because that's the replacement panel they put in for the sample that they took for testing.		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20636/find/
That is an interesting way to do a valley. Do they actually warranty the roof with proximity to salt water?		Eric Novotny An informed customer is the Best Customer! 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20637/find/
Hi Eric. No mention of salt water in the warranty card. Also, our house is in Manila. We're not by the beach; about 20km from Manila Bay. What do you mean by 'interesting way' to do a valley? Would appreciate your opinion on the stone loss.		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20638/find/
The valley looks like it is caulked/cemented together. Not how you normally see it done. Without knowing anymore than you put forth, the granules should not be shedding as they are right now.		Eric Novotny An informed customer is the Best Customer! 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20639/find/
Hi Eric, thanks. Noted re valley. No leaks. Do you think algae can cause stone loss after 4.5 years? There's no discoloration even yet the stones are sloughing off. What other information would help you analyze what's happening? Thank you again.		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20640/find/
I see no reason why the algae would accelerate the failure to that point (i.e. 4.5 years), however, I am basing this assessment on your information only.		Eric Novotny An informed customer is the Best Customer! 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20641/find/
Many thanks Eric. Your expert opinion is appreciated.		Andy Henson 8/31/2015	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20642/find/

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