Roofing Materials

Anyone with building experience have advice of roofing materials? I'm firmly against tar shingles, and will be looking to collect water off the roof. What material is best in terms of minimal toxins added to the water?

Thanks in advance!

I would be interested to know what some people with experience think about the available options. In particular I have been considering metal type roofing something like http://nationalhomecraft.com/metal_roofing.html for the next roof I have to replace. Around here it seems that hail is relatively frequent so not only are the shingles toxic, but they are getting damaged and being replaced once every year or two. I see more and more of these metal roofs around, and even total buildings.

My next roof will definitely be metal. If it is this house, the tar shingles may or may not be removed first (depends on condition and weight load on roof, I would prefer to leave them than landfill them). I will put a layer of foiled foam as insulation and radiant barrier, then sleepers to get the metal 3-4 inches above the existing roof and extend the eaves another 2-3 feet (to give them proper passive solar size for this region). If I can figure out how to avoid wind lift.

Metal, definitely!

We did ours this summer.

We used clay tiles, but I don't know how widely available they are.