diff --git a/docs/user/getting_started.rst b/docs/user/getting_started.rst
index 62e26d1e2613e72d4619deeed8cf9465e270fd38..606e650cb93b62ebc34bb0ab0c61d9914e9259f9 100644
--- a/docs/user/getting_started.rst
+++ b/docs/user/getting_started.rst
@@ -42,6 +42,22 @@ will ensure all packages are rebuilt; this is what you normally want to do after
 will clean the entire tree, so the toolchain will be rebuilt as well, which is
 not necessary in most cases, and will take a while.
 
+
+Environment variables
+---------------------
+
+Gluon's build process can be controlled by various environment variables.
+
+GLUON_SITEDIR
+  Path to the site configuration. Defaults to ``site/``.
+
+GLUON_IMAGEDIR
+  Path where images will be stored. Defaults to ``images/``.
+
+GLUON_BUILDDIR
+  Working directory during build. Defaults to ``build/``.
+
+
 So all in all, to update and rebuild a Gluon build tree, the following commands should be used:
 
 ::
@@ -51,5 +67,3 @@ So all in all, to update and rebuild a Gluon build tree, the following commands
     make update
     make clean
     make
-
-