On one house I actually got very good results putting the antenna in the attic. Benefits included easy reorienting and lack of weather related problems.
If you are mounting outside, pay very good attention to grounding requirements that are required for lightening protection by the National Electric Code.
An inexpensive climbing/support aid you may wish to purchase are roof jacks. These are basically pairs of metal supporting brackets that you mount under a shingle tab with spikes with a 2 x 4 between them. They give very safe support. Use as many pairs as you need to safely get to the mounting location. After installation is complete, disengage the brackets, drive the spikes flush to the shingle, and cover the nail heads with a dap of roofing cement.
If you are mounting outside, pay very good attention to grounding requirements that are required for lightening protection by the National Electric Code.
An inexpensive climbing/support aid you may wish to purchase are roof jacks. These are basically pairs of metal supporting brackets that you mount under a shingle tab with spikes with a 2 x 4 between them. They give very safe support. Use as many pairs as you need to safely get to the mounting location. After installation is complete, disengage the brackets, drive the spikes flush to the shingle, and cover the nail heads with a dap of roofing cement.