A Metal (aluminum) Roof was installed on a 0.5-in-12 roof (my house) in April 2010. CMR assured me that the roof was suitable for the application.
The roof leaked fom the first rains, at the lower edge - capillary action was pulling the water back up under the roof sheets. This problem was confirmed by my observations, 3 industry professionals and my building inspector.
It took a long time for CMR to come out to attempt a repair - I was told this was their busy season. When they eventually came, on 3 occasions they simply tried to apply silicone to fix the problem. IMO this is not a suitable barrier against the elements. Not once did they ever apply water to see the problem, nor did they see the roof in the rain.
With winter approaching, with advice from 3 roofers, the roof was lifted and ice-and-water shield applied. This stopped 90% of the leaking, but the wood was still getting wet.
Without CMR's cooperation, with the water ingress, one winter would damage the engineered beams. I was forced to replace the roof.
To this day CMR tell me that a) the roof wasn't leaking, and b) that I caused the leak. I have good information from a number of industry professionals, websites and aluminum sheeting suppliers (all verbal, nobody wants to put anyrthing in writing) that this type of roof is not suitable for under 2.5 to 3-in-12 roof slopes.
I still maintain aluminum roofing is a good product, I was simply sold the wrong product for the application, and CMR were unwilling to step up to the plate and addmit it. I believe (and I am not alone) that there was no way they could ever have made this roof work. They cite many similar projects being successful. My question is what damage is being done on a constant basis? Small amounts of water leaking oover a period will cause long-term damage, that they will be unaware of. If my roof were out or warranty I would not go back to the original supplier that caused the problem in the first place. Of course they would be unaware of such problems.
I would not recommend CMR because of their lack of product knowledge, dishonest practices and unwillingness to honour their warranties.