Couldn't you have a sample logger defined in your config file, open that in code, and then copy its settings into your dynamically created appender?
log4net.Repository.Hierarchy.Logger l = LogManager.GetLogger(projectName).Logger as log4net.Repository.Hierarchy.Logger log4net.Appender.RollingFileAppender appender = new log4net.Appender.RollingFileAppender(); Log4net.Repository.Hierarchy.Logger sample = LogManager.GetLogger("SampleLog"); appender.AppendToFile = sample.Appender["SampleAppender"].AppendToFile; RobR, probably showing his ignorance