Ask the pros-June 2010
By Reggie Bullard
What are screeds ?
The other side is done the same way. Here, the corner strip is removed preparing for the finish coat. The walls are dead straight. The most important step in plastering is the brown coat, and straightening the brown coat. The finish will follow the contour of the finish, whether it is straight or looks like the ocean. The idea of the finish coat magically making everything look right doesn't work.
Larger walls are more complicated, but the priniple is the same. The screeds illustrated here are called "soft screeds", because the are set and filled at the same time. It is OK in inside plastering to let the screeds set up overnight, as long as care is used to fill in between the screeds, and not over the screeds. A screed in cement if left overnight
will show a hump in the finish coat. I plastered a hallway in a school in Maryland many
years ago with cement plaster, that you can see a hump where every screed was through
the finish. It got late on me, so I left the screeds to set up overnight. I'm not going to tell you where it is, but my plaster chalk boards and stucco ceilings still look fine.