It may look great, but this type of coating can actually damage the aluminum. It tends to peel/crack and allow water to creep under the coating, thereby causing metal rot.
Aluminum roofs should not have any coating. Seams are factory sealed and protrusions should have new putty with limited sealer around the flange.
The exception for coated roofs is Steel. If the roofing material is steel, it does need to be coated. ANYTHING but Elastomeric is better..
I can only judge by what I see, the facts. This 47 year old aluminum roof has been coated almost every year from new. There is NO sign of metal fatigue, rot or corrosion and NO indication of there ever being a leak inside. That's a pretty good product testimonial to me. The key, IMHO, is the preparation. After cleaning, any and all loose or scaly areas must be scrapped and brushed before recoating.
Most all "normal use" older campers I've seen with untreated aluminum roofs have shown moderate to severe interior roof and wall damage from water.
I'll stick to the "Cool Seal", the product has proven it's self to me.
I'm not a roof expert by any means but i did spend a good portion of our spring stripping our aluminum boles roof. The worst part of the 100+ hr 2 ppl stripping was the silver paint sealant, which I'm guess is this cool seal your all are talking about. The good part was that this cool sealant really did protect our trailer for over 50 years. But yes, it did start to fail in cracks which then did hold water. I was also told that it does keep the heat out too. We decided that we did not want to go through the removal process again so we just used VTS's tempro silicone. Now that our roof is smooth we just jack it up and the water just slides right off the back like a slip n slide. Maybe someday we will coat it again with the paint but only when we are too old to care about stripping it again and will let the next generation deal with it! lol.
Hopefully, VTT members understand we are a GOOP FREE ZONE here. Our purpose is correct repairs on vintage trailers and keeping them leak free while retaining a high value for many more years.
Kool Seal is a white elastomeric product designed to reflect UV rays. It does insulate somewhat. The directions on the can state: "not for areas of ponding water". So, if your roof has a dip, and water sits on it, there is a failure. "moisture resistant", 7 year life. From Kool Seal PDF: "DO NOT USE ON FLAT ROOFS WITH A SLOPE OF LESS THAN 1/2 INCH OR LESS PER FOOT. Most vintage trailers do not have a roof slope.
Aluminum Roof Coating, or Silver Slop as we call it, is also designed to reflect and insulate. It "helps increase water resistance" with a 7 year warranty. Very tough and very difficult to remove, dries hard. It certainly is un-necessary on a vintage trailer.
Proper build practices and repairs keep a trailer from leaking, though not everyone is prepared to do that. Replacing old putty is particularly important to keep a trailer water tight. Goops, caulks and coatings are a patch at best. Anyone can coat a roof or slather caulk here and there. While not all roof coatings leak, they are suspect. Why coat a roof that isn't leaking?? Big red flag here.
Lastly: Roof coatings lower the value of a vintage trailer significantly.