Introduced in the 1990’s TPO/PVC is a single-ply roofing membrane that chemically bonds ethylene, propylene, and rubber along with other filler materials.  They are available in light gray, white and black. The light gray or white colors are used in flat roofing today because it is cool due to its solar reflective qualities.  When considering a solar panel installation, the TPO/PVC is a great choice because it increases the efficiency of photovoltaic cells. For durability they feature welded seams. If you are looking for an environmentally friendly solution with long term energy savings – this may be the roof for you.