diff --git a/pkgbuilder/build.py b/pkgbuilder/build.py
index 4b0e209..5a557d8 100644
--- a/pkgbuilder/build.py
+++ b/pkgbuilder/build.py
@@ -437,7 +437,7 @@ def fetch_runner(pkgnames, preprocessed=False):
 
                     except AttributeError:
                         pass
-                allpkgs += pkg
+                allpkgs.append(pkg)
 
         for pkg in allpkgs:
             if not pkg: