I haven't had time to work on the wash house this week. Amend that - I scraped off the egg carton bricks I'd glued onto it. I didn't like the way it was shaping up. Although the bricks were in scale with real size bricks, in place, they looked all wrong. I decided that I needed to cut them a bit bigger, and maybe use something smoother, like card stock. Another option is to score them into the plaster. Since I'm going for a look that's plaster over brick, I'm leaning towards trying the larger, card stock bricks.
I wanted to share this link to Rigid Wrap Plaster Cloth Techniques . It may give you some more ideas how you might want to use the stuff.
I bet you didn't know that the fly swatter was invented in 1905.