diff --git a/lib/utils/post-build.js b/lib/utils/post-build.js
index 8d03569570303..338a8dc4e3dc2 100644
--- a/lib/utils/post-build.js
+++ b/lib/utils/post-build.js
@@ -41,7 +41,7 @@ module.exports = (program, cb) => {
         })
 
         if (page) {
-          newPath = parsePath(page.path).path + parsed.basename
+          newPath = path.join(parsePath(page.path).path, parsed.basename)
         } else {
           // We couldn't find a page associated with this file. Probably
           // the file is in a directory of static files. In any case,