Hello everyone, new here but thought i would chime in.
Here in vancouver, canada some peaks are just insane. We also got all types of roofs (tile, asphalt, metal, plastic, etc). Despite all different roofs, they almost all have something in common, they all have Roof Vents. Remove the roof vents and theres always a solid beam running across. Hook yourself there and you dont have to nail into the roof. This is specially good for tile roofs (you dont have to remove tiles to get to the wood to tie yourself into)
Watch your hands when trying to wrap your rope in there as there usually some type of sharp metal/piece of wood etc just waiting to shred your hands up.
And if youre roof washing dont forget you do have a hole there so spray carefully. Just my 2 cents.
Im not sure how to link a video for you guys so you can get a better idea of what im talking about.
