diff --git a/lib/doc/build.js b/lib/doc/build.js
index e4057260e..92b72dff5 100644
--- a/lib/doc/build.js
+++ b/lib/doc/build.js
@@ -7,7 +7,8 @@ var _ = require('lodash'),
 
 var basePath = path.join(__dirname, '..', '..'),
     docPath = path.join(basePath, 'doc'),
-    readmePath = path.join(docPath, 'README.md');
+    readmePath = path.join(docPath, 'README.md'),
+    fpReadmePath = path.join(docPath, 'fp.md');
 
 var pkg = require('../../package.json'),
     version = pkg.version;
@@ -47,9 +48,10 @@ function onComplete(error) {
 
 function build(type) {
   var options = _.defaults({}, config.base, config[type]),
-      markdown = docdown(options);
+      markdown = docdown(options),
+      filePath = fpFlag ? fpReadmePath : readmePath;
 
-  fs.writeFile(readmePath, postprocess(markdown), onComplete);
+  fs.writeFile(filePath, postprocess(markdown), onComplete);
 }
 
 build(_.last(process.argv));