Discoloration of metal roof

Guest User
9/5/2002
Our home is 2 years old and we have a metal roof. Within the last 6 months it has become discolored on many panels. Some look fine but 50% of the roof is looking black or "tarnished". Our builder says it is not under warranty and it should be painted. The roofer says it is not leaking so therefore it is fine. But it looks very bad. Is this normal? We feel the materials are defective and the builder should replace them. Please advise.
Todd Miller
Isaiah Industries, Inc.
9/5/2002
Without knowing more about whether this was a painted roof or a mill finish roof, it's hard for me to say much. If it's mill finish, it would also be good to know what type of metal it is. You might make sure there are no environmental factors (trees, etc.) causing this. I would highly suggest tracking down the manufacturer of the roofing and posing this question to them. If you want to email photos to me, maybe I can provide further comment. [email protected]
Guest User
12/5/2002
my paint grip steel metal roof was installed 4 years ago and was not painted (left natural). After a very rainy summer, large discoloration spots (which look off white rather than natural gray) have appeared. What is the cause and how can it be fixed?
Todd Miller
Isaiah Industries, Inc.
12/5/2002
I am not terribly familiar with paint grip but I do not believe it is intended to go unpainted. I would suggest you contact the manufacturer of the roofing at this point and inquire with them as to the cause of the discoloration and possible solutions.
Guest User
1/8/2003
PaintGrip is a galvanized product that typically has a zinc phosphate coating in order to enhance paintability. Zinc phosphate is often added to primers as well to enhance corrosion resistance and to help in top coat adhesion. These coatings are not intended as long-life coating but to assist in delaying corrosion in process until final paints are applied. The zinc phospate is intended to be painted in most cases. This treatment is probably weathering from your roof material leaving bare zinc (or zinc alloy) exposed to the environment. The white spots may be zinc-oxide forming on the surface and this is the process in which zinc protects the steel substrate from corroding. If you prefer the bare galvanized look a through cleaning of the roof surface may yield a more uniform appearance and reduce the spotty look for a limited time. If it's appearance is not pleasing then the roof should be painted. You will probably need to clean the roof surface, use an appropriate primer, then topcoat for color and enhanced weatherability following good safety practices. Talk to someone at a paint store (Sherwin Williams, PPG, Duron, MAB, etc) for information on the appropriate steps to paint this correctly. I don't think personnel at a big box or DIY store will have the appropriate knowledge for your needs. Of course, a reputable paint contractor should also know the best way to coat this roof if you choose to hire for this service. For longer life use a high quality paint -- when it comes to paint, you really do get what you pay for.
Guest User
5/30/2003
My 5500 sf Acrylume SSR was finished in Sept 2001. In Sept 2002 my roofer alerted me that some of his installs had problems with panels darking. At that time I did not have any sign of problems. Two months later panels began to uniformliy darken. The panel problems continued until about 60% of all panels had uniformly darkened with the rest remaining with a high reflective finish. The supplier and factory reps visited the site and said that acrylume was an "unfinished product" and that the darkening was inherent in the product and not a defect. They present literature indicating that the darkend panels were probably even more durable beause of the process. After my own research into the Galvalume/Acrylume products I find that US Steel touts the Acrylume product as being and Energy Star qualified product noted "for its high reflectivity with its attendant energy effectiviness. I also found a test report done by Lockheed Martin Energy Research Corporation at the Oak Ridge National Labortories who carried out the test to certify the Acrylic coated products for the Energy Star designation. The report indicates that to qualify the panel must show a high relfectivity and to demostrate that the limited degradation of reflectivity over a three year period. The darkend panels on my roof are signficantly darkend. Darkening occurs randomly across the panels and all darkend panels are unifromly darkend, i.e. I have two distinct tones of panels --one group has high refledctiivty and one group is dull. In addition, all panels are showing black streaks. All panels were uniform and consitent for the first 14 months after initial install. On added bit of information. We have a flat roof dormer that does not have a gutter and thus has a drip line line on the darkened roof panels below it. It is now begining to look like drip line is starting to lighten up as if it were wearing away the surface coating on the panels (acrylume?). W
Guest User
5/30/2003
My 5500 SF Acrylume SSR was finished in Sept 2001. In Sept 2002 my roofer alerted me that some of his installs had begun showing problems with panels darking. At that time I did not have any sign of problems. Two months later panels began to uniformliy darken. The panel problems continued until about 60% of all panels had uniformly darkened with the rest remaining with a high reflective finish. The supplier and factory reps visited the site and said that Acrylume was an "unfinished product" --like lumber and that the darkening was inherent in the product and not a defect. They presented literature indicating that the darkend panels were probably even more durable because of the darking process. After my own research into the Galvalume/Acrylume products I find that US Steel touts the Acrylume product as being and Energy Star qualified product noted "for its high reflectivity with its attendant energy effectiviness. I also found a test report done by Lockheed Martin Energy Research Corporation at the Oak Ridge National Labortories who carried out the test to certify the Acrylic coated products for the Energy Star designation. The report indicates that to qualify the panel must show a high relfectivity and to demostrate that they have limited degradation of reflectivity over a three year period. The darkend panels on my roof are signficantly darkend. Darkening occurs randomly in panels across the roof and all darkend panels are unifromly darkend, i.e. I have two distinct tones of panels --one group has high refledctiivty and one group is dull. There are no variations in individual panels. They are either dark or they are bright. In addition, all panels are showing black streaks. All panels were uniformly bright and consisitent for the first 14 months after initial install. One added bit of information. We have a flat roof dormer that does not have a gutter and thus has a drip line on the darkened roof panels below it. It is now begining to look like drip line is starting to lighten up as if the water was wearing away the surface coating on the panels (acrylume?). We are at a loss as to where to go from here. The manufacturers cannot have it both ways. They tout Acrylume for its durability and Energy Star rating and then claim darkening is an inherent characteristic when the panels begin change colors. Nowhere in the sales literature is there any warning given about the possibility of the discoloration probem. I note that "oil canning" is alway pointed out by all producers but there is no mention of the discoloration problem which has a much greater impact on appearance. These roofs cost a fortune to put up and nobody in his right mind would install Acrylume if they knew they were running the risk of this kind of disfiuguration. We are not talking about nit picking color differences here. These panel are so distinctly different that even a small child will ask when seeing the house for the first time "Whats the matter with your roof?" If you read up on all the claims made about the wonderful properties of Acrylume and then look at the roof in question you would not believe they were the same products. I would appreciate your input.
Allan Reid
Dura-Loc Roofing Systems, Inc.
5/30/2003
Looks like Todd left this one to me. We manufacture a metal roof panel from acrylic coated Galvalume and have only experienced this when a customer mixed differing batches of steel. Galvalume steel used for rollformed vertical rib products is typically temper levelled to ensure flatness of sheet. The Galvalume coating is suceptable to staining from oils used in the roll forming process or even from the installers hands. The acrylic coating that is applied acts as a protectant layer and elliminates the need for oils however it is designed to dissipate off the material within a year or so. Having said that I would have the supplied check to see if the steel came frome the same batch. The Galvalume should darken as the coating dissipatesto a soft pateina somewhat like a slight tarnish on silver. It is possible that the brighter sheets have a slightly thicker coating of acrylic and that vit will start to darken itself and catch up to the other sheets within a year. As to the drip, if the sheets above still have the acrylic on them then, the rain water run off will be very aggitated and aggressive when it lands on the lowere sheet. This as well should go away within a year. I'd appreciate if you would let me know later how the roof is doing.
Allan Reid
Dura-Loc Roofing Systems, Inc.
5/30/2003
Looks like Todd left this one to me. We manufacture a metal roof panel from acrylic coated Galvalume and have only experienced this when a customer mixed differing batches of steel. Galvalume steel used for rollformed vertical rib products is typically temper levelled to ensure flatness of sheet. The Galvalume coating is suceptable to staining from oils used in the roll forming process or even from the installers hands. The acrylic coating that is applied acts as a protectant layer and elliminates the need for oils however it is designed to dissipate off the material within a year or so. Having said that I would have the supplied check to see if the steel came frome the same batch. The Galvalume should darken as the coating dissipatesto a soft pateina somewhat like a slight tarnish on silver. It is possible that the brighter sheets have a slightly thicker coating of acrylic and that vit will start to darken itself and catch up to the other sheets within a year. As to the drip, if the sheets above still have the acrylic on them then, the rain water run off will be very aggitated and aggressive when it lands on the lowere sheet. This as well should go away within a year. I'd appreciate if you would let me know later how the roof is doing.
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