A. Ron Webber, owner of Prime Plastering in Irvine, Calif., responds: Repairing a damaged rounded corner is handled like any other repair job. Assuming that the corner has been hit, and a chunk of stucco has been knocked out, the loose and damaged stucco should be chipped back. Carefully tuck the top of the weather barrier patch under the existing weather barrier, creating a lap, so that the weather barrier keeps out the water.
Then install the wire or metal lath, again lapping the old and the new by about 2 inches. If there is nothing to nail to at the repair location, then you can tie the lath together using tie wire. Now you’re ready to install the stucco base coat, taking care to maintain the desired shape. If it is a heavy fill, you may need to do it in two coats....
to read the full article.