Protected Membrane Roof
From Open Source Ecology
- 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]
- Why no overhangs?
- For regular buildings, general comments is they help greatly with water intrusion but cause extra uplift. 170 lb uplift per truss 2' OC with 80 mph wind. [5]. In our case, if we have 20 psf dead load, there is 160' of load in 4' of roof edge, so that effectively cancels, not to mention nails and hurricane ties. Hurricane ties are 200-1000 lb uplift each [6].
