I'll be doing a series of tasks near the top of a nine-foot ceiling. I'll be: cleaning; repairing plaster; cleaning and sanding old trim; and priming and painting ceilings, walls and trim, including a lot of cutting in around trim and edges. I'm wary of attempting this with a simple stepladder, as I saw a plasterer do recently (he simply stood on the top steps to work up high). Is there a special ladder that will support this work up high, or do I have to use an extension ladder propped against the wall? Thanks.