Shed's link is ok if the circumstances you are working in apply. When I was a child the house we were in had a landing and rail which meant one could look over the rail down the stairs, and this was invaluable in setting up something stable. A house I now have is narrow, has a circular turn at the top which is unsuitable to placing any sort of ladder and enclosed. I have already had a combi type ladder fall away from under me because I'd not checked all I thought I had. And now up in "platform mode" it barely fits widthwise and when up just give one a level just the height of the top stair anyway ! Near useless. So the only alternative I can see is to try to find something else to balance on top, which has to be very risky. I'm unsure how one is expected to decorate it. No wonder the last owners put in that dodgy claustrophobic false ceiling. Meanwhile I'm still wondering how to tackle it safely.