GPW wrote:R value of the pink stuff ???
Looks like R4 in the photo above.
I painted the top of my cargo trailer recently also. I have not yet put the insulation in and just the white paint makes a lot of difference. I wanted the trailer to look rather "stock" so I painted only the top side, leaving the rolled over portion raw, this was an intentional compromise. You don't see the paint from normal eye level. You can readily feel the temperature difference of the sheet metal from inside the trailer, painted vs. raw, when the sun is bearing down, even at 9:00am. Slow the initial heat gain with a reflective color then slow the heat transmission with insulation. White works fairly well as a color. I've tried samples of silver and they didn't do as well.
Most of the garden variety of cargo trailers that I've seen will use a galvanized steel roof. They may use an aluminum wrap over the curved portion of the roof as in Jeffmo63's trailer, but dollars to donuts the inner section that was painted is galvanized steel. Easy to check with a magnet. So the trick is properly cleaning and priming for a galvanized surface, which your local paint dealer can help you with. Painting galvanized can be tricky.
I painted a cargo trailer roof about eight years ago and went with a Sherwin-Williams primer called Galvite HS. This stuff is a little spendy but it will stick to the metal. The only surface preparation that I did was to wash the roof with a little dish detergent and water to get any dirt off. Paint applied with roller, and brush for the details...it doesn't have to look great on top of a cargo trailer, just function. My brother owns the first trailer that I painted and there have been no problems with adhesion, it lives out in the weather. Both trailers were topcoated with S-W DTM acrylic water-borne paint. I just didn't want to have to deal with peeling paint in the future.
Bruce
