Protected Membrane Roof

• 12 psf ballast required - example when wet and dry for living roof - [1]
• Dupont has a version where insulation and ballast lies on top of the membrane. [2]
• Comparison of PMR aka Inverted Roof Membrane Assembly to Conventional Membrane Roof. [3]
• Why is standard membrane roof not called Protected Membrane Roof if ballast protects the membrane?
• Brief history of membrane roofing [4]