diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -6511,6 +6511,7 @@
     'HarbormasterBuildLog' => array(
       'HarbormasterDAO',
       'PhabricatorPolicyInterface',
+      'PhabricatorDestructibleInterface',
     ),
     'HarbormasterBuildLogChunk' => 'HarbormasterDAO',
     'HarbormasterBuildLogChunkIterator' => 'PhutilBufferedIterator',
diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php b/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
--- a/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuildLog.php
@@ -2,7 +2,9 @@
 
 final class HarbormasterBuildLog
   extends HarbormasterDAO
-  implements PhabricatorPolicyInterface {
+  implements
+    PhabricatorPolicyInterface,
+    PhabricatorDestructibleInterface {
 
   protected $buildTargetPHID;
   protected $logSource;
@@ -317,7 +319,55 @@
 
   public function describeAutomaticCapability($capability) {
     return pht(
-      "Users must be able to see a build target to view it's build log.");
+      'Users must be able to see a build target to view its build log.');
+  }
+
+
+/* -(  PhabricatorDestructibleInterface  )----------------------------------- */
+
+
+  public function destroyObjectPermanently(
+    PhabricatorDestructionEngine $engine) {
+    $this->destroyFile($engine);
+    $this->destroyChunks();
+    $this->delete();
+  }
+
+  public function destroyFile(PhabricatorDestructionEngine $engine = null) {
+    if (!$engine) {
+      $engine = new PhabricatorDestructionEngine();
+    }
+
+    $file_phid = $this->getFilePHID();
+    if ($file_phid) {
+      $viewer = $engine->getViewer();
+      $file = id(new PhabricatorFileQuery())
+        ->setViewer($viewer)
+        ->withPHIDs(array($file_phid))
+        ->executeOne();
+      if ($file) {
+        $engine->destroyObject($file);
+      }
+    }
+
+    $this->setFilePHID(null);
+
+    return $this;
+  }
+
+  public function destroyChunks() {
+    $chunk = new HarbormasterBuildLogChunk();
+    $conn = $chunk->establishConnection('w');
+
+    // Just delete the chunks directly so we don't have to pull the data over
+    // the wire for large logs.
+    queryfx(
+      $conn,
+      'DELETE FROM %T WHERE logID = %d',
+      $chunk->getTableName(),
+      $this->getID());
+
+    return $this;
   }
 
 
diff --git a/src/applications/harbormaster/worker/HarbormasterLogWorker.php b/src/applications/harbormaster/worker/HarbormasterLogWorker.php
--- a/src/applications/harbormaster/worker/HarbormasterLogWorker.php
+++ b/src/applications/harbormaster/worker/HarbormasterLogWorker.php
@@ -62,20 +62,7 @@
     }
 
     if ($is_force) {
-      $file_phid = $log->getFilePHID();
-      if ($file_phid) {
-        $file = id(new PhabricatorFileQuery())
-          ->setViewer($viewer)
-          ->withPHIDs(array($file_phid))
-          ->executeOne();
-        if ($file) {
-          id(new PhabricatorDestructionEngine())
-            ->destroyObject($file);
-        }
-        $log
-          ->setFilePHID(null)
-          ->save();
-      }
+      $log->destroyFile();
     }
 
     if (!$log->getFilePHID()) {