diff --git a/src/Commands/core/SiteInstallCommands.php b/src/Commands/core/SiteInstallCommands.php
index ceaef9ee47..568b1c611f 100644
--- a/src/Commands/core/SiteInstallCommands.php
+++ b/src/Commands/core/SiteInstallCommands.php
@@ -269,12 +269,17 @@ public function pre(CommandData $commandData) {
     else {
       $this->logger()->info(dt('Sites directory @subdir already exists - proceeding.', array('@subdir' => $conf_path)));
     }
+    // Quietly try to make the conf_path directory writable for re-installs.
+    @chmod($conf_path, 0777);
 
     if (!drush_file_not_empty($settingsfile)) {
       if (!drush_op('copy', 'sites/default/default.settings.php', $settingsfile) && !drush_get_context('DRUSH_SIMULATE')) {
         throw new \Exception(dt('Failed to copy sites/default/default.settings.php to @settingsfile', array('@settingsfile' => $settingsfile)));
       }
     }
+    // Quietly try to make settings.php writable for re-installs. We will let the
+    // Drupal installer report any problems.
+    @chmod($settingsfile, 0666);
 
     // Write an empty sites.php if we using multi-site.
     if ($sitesfile_write) {