renaming folders only works with chmodd 777

I’m using the following code in a plugin to rename a folder in the uploads folder according to the date, but this only works if the chmodd settings of both folders are 777. How can I change this code so I can use at least chmodd 755 to keep my website save.

date_default_timezone_set('Europe/Amsterdam'); // set timezone
$foldername = ''; $source = 'uploads';
$allfolders = getDirectory($source); // get folders
$folder = $source.'/'.$allfolders[0]; // get first folder
$month = (int)date('n');
$day = (int)date('j');
$f = 50-$day; $s = 100-$month;
$newfolder = $source.'/'.(string)$f.(string)$s; if($folder != '' && $folder != $newfolder){
rename($folder, $newfolder);
$foldername = $newfolder."/";
}else if($folder == $newfolder){
$foldername = $newfolder."/";
}
else{ $foldername = 'error';
}