PLEASE CAN YOU HELP. I HAVE A FLAT ROOF, WHICH IS A KITCHEN EXTENSION, CAN YOU WALK ON THIS ROOF? WHAT WIEGHT CAN THEY TAKE? HOW LONG DOES THE FELT LAST? I HAVE MOSS GROWING IN A PATCH NEAR THE MAIN HOUSE ROOF, (THE FLAT ROOF SEAMS TO TUCK-UNDER THE MAIN ROOF)DOES THIS MEAN THAT THERE IS A PROBLEM? ...
