diff --git a/config/RemoveBuildDirectoryPlugin.js b/config/RemoveBuildDirectoryPlugin.js
new file mode 100644
index 0000000..944e7d3
--- /dev/null
+++ b/config/RemoveBuildDirectoryPlugin.js
@@ -0,0 +1,39 @@
+// @flow
+
+const fs = require("fs");
+const path = require("path");
+const rimraf = require("rimraf");
+
+// Note: the following type-import just resolves to `any`.
+/*:: import type {Compiler} from "webpack"; */
+
+module.exports = class RemoveBuildDirectoryPlugin {
+  apply(compiler /*: Compiler */) {
+    if (compiler.hooks) {
+      console.warn(
+        "" +
+          "You appear to be running Webpack >= 4. " +
+          "The RemoveBuildDirectoryPlugin should be forward-compatible, " +
+          "but you should update it to use the new APIs. See " +
+          "<https://github.com/webpack/webpack/releases/tag/v4.0.0-beta.0> " +
+          "for details."
+      );
+    }
+    compiler.plugin("compile", () => {
+      const outputPath = compiler.options.output.path;
+      // If a build config has no `output.path` property, and no
+      // `--output-path` is passed on the command line, then Webpack
+      // will default to building into the current directory. Removing
+      // the whole Git repository would be mighty rude, so we protect
+      // against that case.
+      if (fs.existsSync(path.join(outputPath, ".git"))) {
+        throw new Error(
+          "Refusing to remove build directory with a Git repository: " +
+            outputPath
+        );
+      }
+      console.warn("Removing build directory: " + outputPath);
+      rimraf.sync(outputPath);
+    });
+  }
+};
diff --git a/config/makeWebpackConfig.js b/config/makeWebpackConfig.js
index 288cb18..b33d272 100644
--- a/config/makeWebpackConfig.js
+++ b/config/makeWebpackConfig.js
@@ -4,7 +4,7 @@ const express = require("express");
 const os = require("os");
 const path = require("path");
 const webpack = require("webpack");
-const CleanPlugin = require("clean-webpack-plugin");
+const RemoveBuildDirectoryPlugin = require("./RemoveBuildDirectoryPlugin");
 const ManifestPlugin = require("webpack-manifest-plugin");
 const SWPrecacheWebpackPlugin = require("sw-precache-webpack-plugin");
 const StaticSiteGeneratorPlugin = require("static-site-generator-webpack-plugin");
@@ -259,7 +259,7 @@ function plugins(mode /*: "development" | "production" */) {
   ];
   const prodOnlyPlugins = [
     // Remove the output directory before starting the build.
-    new CleanPlugin([paths.appBuild], {root: paths.root}),
+    new RemoveBuildDirectoryPlugin(),
     // Minify the code.
     new webpack.optimize.UglifyJsPlugin({
       compress: {
diff --git a/package.json b/package.json
index d9dabaf..3ee4e09 100644
--- a/package.json
+++ b/package.json
@@ -60,6 +60,7 @@
     "prettier": "^1.13.4",
     "raf": "3.4.0",
     "react-dev-utils": "^5.0.0",
+    "rimraf": "^2.6.2",
     "static-site-generator-webpack-plugin": "^3.4.1",
     "style-loader": "0.19.0",
     "sw-precache-webpack-plugin": "0.11.4",
diff --git a/yarn.lock b/yarn.lock
index 8c963ac..f03395e 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6749,7 +6749,7 @@ right-align@^0.1.1:
   dependencies:
     align-text "^0.1.1"
 
-rimraf@2, rimraf@^2.2.8, rimraf@^2.5.1, rimraf@^2.5.4, rimraf@^2.6.1:
+rimraf@2, rimraf@^2.2.8, rimraf@^2.5.1, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.6.2:
   version "2.6.2"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.2.tgz#2ed8150d24a16ea8651e6d6ef0f47c4158ce7a36"
   dependencies: