diff --git a/src/lib/Hydra/Controller/Build.pm b/src/lib/Hydra/Controller/Build.pm
index 52bf9d99..6c7521a3 100644
--- a/src/lib/Hydra/Controller/Build.pm
+++ b/src/lib/Hydra/Controller/Build.pm
@@ -357,26 +357,12 @@ sub restart : Chained('build') PathPart Args(0) {
     my $build = $c->stash->{build};
 
     requireProjectOwner($c, $build->project);
+    
+    my $drvpath = $build->drvpath ;
+    error($c, "This build cannot be restarted.")
+        unless $build->finished && -f $drvpath ;
 
-    txn_do($c->model('DB')->schema, sub {
-        my $drvpath = $build->drvpath ;
-        error($c, "This build cannot be restarted.")
-            unless $build->finished && -f $drvpath ;
-
-        my $cmd = "`nix-store -qR $drvpath`";
-        my $r = `nix-store --clear-failed-paths $cmd`;
-  
-        $build->update({finished => 0, timestamp => time});
-
-        $build->resultInfo->delete;
-
-        $c->model('DB::BuildSchedulingInfo')->create(
-            { id => $build->id
-            , priority => 0 # don't know the original priority anymore...
-            , busy => 0
-            , locker => ""
-            });
-    });
+    restartBuild($build);
 
     $c->flash->{buildMsg} = "Build has been restarted.";
     
diff --git a/src/lib/Hydra/Helper/AddBuilds.pm b/src/lib/Hydra/Helper/AddBuilds.pm
index f1b66a1e..791ae17f 100644
--- a/src/lib/Hydra/Helper/AddBuilds.pm
+++ b/src/lib/Hydra/Helper/AddBuilds.pm
@@ -12,7 +12,7 @@ use File::stat;
 use File::Path;
 
 our @ISA = qw(Exporter);
-our @EXPORT = qw(fetchInput evalJobs checkBuild inputsToArgs captureStdoutStderr getReleaseName getBuildLog addBuildProducts);
+our @EXPORT = qw(fetchInput evalJobs checkBuild inputsToArgs captureStdoutStderr getReleaseName getBuildLog addBuildProducts restartBuild);
 
 sub scmPath {
     return getHydraPath . "/scm" ;
@@ -764,3 +764,30 @@ sub checkBuild {
 
     return $build;
 };
+
+
+sub restartBuild {
+    my ($db, $build) = @_;
+
+    txn_do($db, sub {
+        my $drvpath = $build->drvpath ;
+        my $outpath = $build->outpath ;
+
+        my $paths = "";
+        foreach my $bs ($build->buildsteps) {
+          $paths = $paths . " " . $bs->outpath;
+        }
+
+        my $r = `nix-store --clear-failed-paths $paths $outpath`;
+        $build->update({finished => 0, timestamp => time});
+
+        $build->resultInfo->delete;
+
+        $db->resultset('BuildSchedulingInfo')->create(
+            { id => $build->id
+            , priority => 0 # don't know the original priority anymore...
+            , busy => 0
+            , locker => ""
+            });
+    });
+}