There are still many roofs that are covered with stone. What is the stone doing? TPO, EPDM Rubber and Torch Down roofs do not automatically come with Ultraviolet protection. These single-ply membranes are susceptible to ultraviolet degradation. Most roofing contractors will not let the owner know that the roof needs protection. EPDM rubber and TPO does not have built-in ultraviolet protection as many salesmen might advertise. I am not sure, but there might be some coatings available for these two products.
Modified Bitumen Torch Down Rubber membranes have many options for protection. The most common one is Silver Coating or Aluminum Asphalt paint. Most roofers will install the plain Modified Bitumen Torch Down and either leave it up to the owner to have it coated or offer an additional charge to do the protective coating.
The other option is to have a roofer install a Modified Bitumen Torch Down Rubber with the ceramic granules already embedded into the membrane. This is the best protective coating for a rubber membrane.
The other option is to add stone over the rubber membrane. Watch the video to see how it is done.
0:00 What are stones for on a roof
0:34 Gravel up ladder lift
1:10 3 Roofing systems
2:23 Torch Down Membrane
3:00 Spider Cracks due to ultraviolets
3:35 Ceramic granules protecting membrane
4:25 What is the stone for?
6:02 Raking the stone on the roof
6:55 End