diff --git a/lib/pipeline/pipeline.js b/lib/pipeline/pipeline.js
index 53dda9af..87e8d38c 100644
--- a/lib/pipeline/pipeline.js
+++ b/lib/pipeline/pipeline.js
@@ -16,6 +16,8 @@ class Pipeline {
     this.webpackConfigName = options.webpackConfigName;
     this.pipelinePlugins = this.plugins.getPluginsFor('pipeline');
     this.isFirstBuild = true;
+
+    fs.removeSync(this.buildDir);
   }
 
   build(abi, contractsJSON, path, callback) {