Monier 2000 slate – stated weight is 950lbs. per square. Does that include underlayment or is it tile only?
The published weight of all MonierLifetile products is for only the tile. Your actual design will consist of the combined dead load and live load factors. Your message does not state where in Northern California you are, but unless you are situated in the mountains where snow load must be considered, your design live load will probably be 20 psf (pounds per square foot). This factor is the same, regardless of which type of roofing material you choose. The dead load is a compilation of all of the roofing and framing components and represents the static weight that is constantly being supported. This includes the roofing material, underlayment, roof sheathing and rafter system. Unless other components such as solar panels or roof mounted mechanical apparatus are added, the dead load for a 9.5 psf roofing tile would typically be around 14 to 15 psf.
