I heard about new roofing underlayment systems that use a layer of isocyanurate foam with ridges to vent the air so the attic won't get so hot. I am thinking about something like this for my house because I'm going to replace the roof with concrete tile later this year. My attic currently has zero insulation, but I need to insulate up there. However if I put insulation between the ceiling joists, it will be really hard to do all the electrical/plumbing remodeling work that I plan to do in the next 5-10 years. So these new roofing systems sound attractive.. so I can insulate at the roof level and don't have to put as much insulation in the attic itself that would bury all the wires and pipes and fixtures.. How well do these new roofing systems work? Any particular brands to look at?

Has anyone installed a product similar to gutter helmet or gutterguard yourself? If so, what product did you use and are you satisfied with the outcome? Any tips on installation process? Thanks, Tennisman