C# Append lines to a file using a StreamWriter

gistfile1.cs

   StringBuilder strBuilLog = new StringBuilder();
            string strLogData = "Welcome to log data \t";
            strBuilLog.Append(strLogData);
            string strLogData2 = "Welcome to log data 2" + Environment.NewLine;
            strBuilLog.Append(strLogData2);
            string strLogDataFinal = "Welcome to log data final \t";
            strBuilLog.Append(strLogDataFinal);

            using (StreamWriter strwLog = new StreamWriter("c:\\log.txt"))
            {
                strwLog.Write(strBuilLog.ToString());
                strwLog.Close();
            }