diff --git a/gulpfile.coffee b/gulpfile.coffee
index 79fb493..7663af8 100644
--- a/gulpfile.coffee
+++ b/gulpfile.coffee
@@ -27,14 +27,17 @@ gulp.task 'copy:manifest', ->
     .pipe gulp.dest('dist')
 
 gulp.task 'copy:images', ->
+  del.sync 'dist/images'
   gulp.src 'src/images/*'
     .pipe gulp.dest('dist/images')
 
 gulp.task 'copy:vendor', ->
+  del.sync 'dist/vendor'
   gulp.src 'vendor/**/*'
     .pipe gulp.dest('dist/vendor')
 
 gulp.task 'haml', ->
+  del.sync 'dist/html'
   gulp.src 'src/haml/*.haml'
     .pipe plumber
       errorHandler: notify.onError('Error: <%= error.message %>')
@@ -62,6 +65,7 @@ gulp.task 'coffee:popup', ->
   .pipe gulp.dest('dist/javascripts')
 
 gulp.task 'sass', ->
+  del.sync 'dist/stylesheets'
   gulp.src 'src/sass/*.sass'
     .pipe plumber
       errorHandler: notify.onError("Error: <%= error.message %>")
@@ -69,13 +73,7 @@ gulp.task 'sass', ->
       indentedSyntax: true
     .pipe gulp.dest('dist/stylesheets')
 
-gulp.task 'build', ['clean'], ->
-  gulp.start 'copy:manifest'
-  gulp.start 'copy:images'
-  gulp.start 'copy:vendor'
-  gulp.start 'haml'
-  gulp.start 'coffee'
-  gulp.start 'sass'
+gulp.task 'build', ['copy:manifest', 'copy:images', 'copy:vendor', 'haml', 'coffee', 'sass']
 
 gulp.task 'watch', ->
   gulp.watch 'src/manifest.json', ['copy:manifest']
diff --git a/wercker.yml b/wercker.yml
index fa9f914..8ab0f85 100644
--- a/wercker.yml
+++ b/wercker.yml
@@ -12,7 +12,7 @@ build:
           echo "npm version $(npm -v) running"
     - script:
         name: create dist
-        code: npm run zip
+        code: npm run zip && test -e dist-$(npm run app_version --silent).zip
 deploy:
   steps:
     - script: