The Magnum Roof System of the latest Jayco hybrids are made on a wood frame and are slightly bowed as opposed to completely flat. The sides are vacuum laminate, Jayco's name being "Tuffshell". They use aluminum frame for the walls.
We just traded our 2003 Kiwi 17a that had the Tuffshell construction. Aside from the fact that the front and back bed panels oxidized and lost their shine, the trailer looked great. Check all the seams (especially roof!) several times a year and its will last for many years.
