We've had two quotes from roofers to replace our garage roof, one uses just felt and suggested that the silver covering on a flat roof we had replaced on our extension last year needed re-painting every two years and was harder to maintain. The second guy uses the silver covering (or black) over the felt.
We are just not sure which would be best and are now worried about the regular maintanence involved with our exisitng roof.
What is the purpose of the silver paint. Is it to be solar reflective? There are alternative felts which do not require solar reflective coverings and hence no maintenance.
Alternatively you could use chippings on the roof covering which again need no maintenance.
I would assume that the other prodcuts mentioned in replies will be more expensive, but no harm in seeking plenty of estimates. Also make sure the product provides an insurance backed guarantee, usually 20 years I believe.