diff --git a/setup.py b/setup.py
index 91602f54a..c56df38c5 100644
--- a/setup.py
+++ b/setup.py
@@ -35,12 +35,7 @@ import sys
 import glob
 import codecs
 import commands
-
-# determine if the computer has ability to change file permissions or not?
-if hasattr(os, 'chmod'):
-    _has_chmod = True
-else:
-    _has_chmod = False
+from stat import ST_MODE
 
 VERSION = '3.5.0'
 ALL_LINGUAS = ('bg', 'ca', 'cs', 'da', 'de', 'en_GB', 'es', 'fi', 'fr', 'he',
@@ -215,11 +210,11 @@ def write_gramps_script(install_cmd, build_scripts):
     f_out.write('exec %s -O $GRAMPSDIR/gramps.py "$@"\n' % sys.executable)
     f_out.close()
 
-    # set eXecute bit for gramps startup script...
-    # this is required for both Linux and MacOS 
-    if _has_chmod:
-        log.info('Changing permissions of %s from 644 to 775', filename)
-        os.chmod(filename, 0775)
+    if os.name == 'posix':
+        # set read and execute bits
+        mode = ((os.stat(filename)[ST_MODE]) | 0555) & 07777
+        log.info('changing mode of %s to %o', filename, mode)
+        os.chmod(filename, mode)
 
 def write_const_py(install_cmd):
     '''
@@ -282,11 +277,6 @@ class install(_install):
         else:
             update_posix()
 
-        # change permissions of build directory after installation
-        # so it can be deleted by normal user...
-        if _has_chmod:
-            os.system('chmod -R 777 build')
-
 DOC_FILES = ['AUTHORS', 'COPYING', 'FAQ', 'INSTALL', 'NEWS', 'README', 'TODO']
 GEDCOM_FILES = glob.glob(os.path.join('example', 'gedcom', '*.*'))
 GRAMPS_FILES = glob.glob(os.path.join('example', 'gramps', '*.*'))