diff --git a/tools/build_ui.sh b/tools/build_ui.sh
index ace0ee3ac..d19e39be3 100755
--- a/tools/build_ui.sh
+++ b/tools/build_ui.sh
@@ -37,5 +37,7 @@ echo "]" >> $init
 cat $temp >> $init
 rm $temp
 
-echo "Building resources.."
-pyrcc4 designer/icons.qrc -o aqt/forms/icons_rc.py
+if [ designer/icons.qrc -nt aqt/forms/icons_rc.py ]; then
+    echo "Building resources.."
+    pyrcc4 designer/icons.qrc -o aqt/forms/icons_rc.py
+fi