The lockup im buying has got corrugated roof that I'm going to assume is asbestos as I don't know.  I need to get up on it to remove ivy.  Its a fairly shallow roof, with a fall of about a foot over the 15 foot width.  It is supported at either and and along the middle with timbers.

Helpfully, I've only got access from one end.  Is it likely to be OK to just lie a roof ladder direct onto it, or am I going to need to stick something else under it to spread the load more?

The building is roughly 15x40 foot, and I've only got access from one 15 foot end currently.  The other end might be accessible in a few weeks, if I can get the door that end to open (its an outward opening pedestrian door that is currently blocked by ivy on the outside - hoping to get it open with a sawzall)

Started clearing it out.  6 huge bags of ivy gone from the inside for starters, and I'm only half way into it  

Having put up a couple of temporary lights inside so we could work after dark, I could see the state of the timber that supports the roof.  It looks like rain has been running along the ivy stems and soaking the wood, meaning that most of it is now rather rotten.

Got an asbestos specialist coming out next week to quote for taking the roof off complete with ivy, and replacing with insulated corrugated steel.  Saves me worrying about removing the ivy i guess, but its going to be more than I was hoping to spend.

Do you mean in terms of anti-theft or in terms of having the roof fall on my head?