diff --git a/mkdocs/commands/build.py b/mkdocs/commands/build.py
index 052f6b56..ae622bfb 100644
--- a/mkdocs/commands/build.py
+++ b/mkdocs/commands/build.py
@@ -64,6 +64,7 @@ def get_context(nav, config, page=None):
 
 
 def build_template(template_name, env, config, site_navigation=None):
+    """ Build a template using the theme environment. """
 
     log.debug("Building template: %s", template_name)
 
@@ -80,7 +81,29 @@ def build_template(template_name, env, config, site_navigation=None):
     return True
 
 
+def build_error_templates(templates, env, config, site_navigation):
+    """
+    Build error templates.
+
+    Force absolute URLs in the nav of error pages and account for the
+    possability that the docs root might be different than the server root.
+    See https://github.com/mkdocs/mkdocs/issues/77
+    """
+
+    site_navigation.url_context.force_abs_urls = True
+    default_base = site_navigation.url_context.base_path
+    site_navigation.url_context.base_path = utils.urlparse(config['site_url']).path
+
+    for template in templates:
+        build_template(template, env, config, site_navigation)
+
+    # Reset nav behavior to the default
+    site_navigation.url_context.force_abs_urls = False
+    site_navigation.url_context.base_path = default_base
+
+
 def _build_page(page, config, site_navigation, env, dirty=False):
+    """ Build a Markdown page and pass to theme template. """
 
     # Process the markdown text
     page.load_markdown()
@@ -102,8 +125,9 @@ def _build_page(page, config, site_navigation, env, dirty=False):
 
 
 def build_extra_templates(extra_templates, config, site_navigation=None):
+    """ Build user templates which are not part of the theme. """
 
-    log.debug("Building extra_templates page")
+    log.debug("Building extra_templates pages")
 
     for extra_template in extra_templates:
 
@@ -120,9 +144,8 @@ def build_extra_templates(extra_templates, config, site_navigation=None):
 
 
 def build_pages(config, dirty=False):
-    """
-    Builds all the pages and writes them into the build directory.
-    """
+    """ Build all pages and write them into the build directory. """
+
     site_navigation = nav.SiteNavigation(config)
     loader = jinja2.FileSystemLoader(config['theme_dir'] + [config['mkdocs_templates'], ])
     env = jinja2.Environment(loader=loader)
@@ -130,16 +153,7 @@ def build_pages(config, dirty=False):
     env.filters['tojson'] = filters.tojson
     search_index = search.SearchIndex()
 
-    # Force absolute URLs in the nav of error pages and account for the
-    # possability that the docs root might be different than the server root.
-    # See https://github.com/mkdocs/mkdocs/issues/77
-    site_navigation.url_context.force_abs_urls = True
-    default_base = site_navigation.url_context.base_path
-    site_navigation.url_context.base_path = utils.urlparse(config['site_url']).path
-    build_template('404.html', env, config, site_navigation)
-    # Reset nav behavior to the default
-    site_navigation.url_context.force_abs_urls = False
-    site_navigation.url_context.base_path = default_base
+    build_error_templates(['404.html'], env, config, site_navigation)
 
     if not build_template('search.html', env, config, site_navigation):
         log.debug("Search is enabled but the theme doesn't contain a "
@@ -151,7 +165,6 @@ def build_pages(config, dirty=False):
     build_extra_templates(config['extra_templates'], config, site_navigation)
 
     for page in site_navigation.walk_pages():
-
         try:
             # When --dirty is used, only build the page if the markdown has been modified since the
             # previous build of the output.
@@ -171,9 +184,8 @@ def build_pages(config, dirty=False):
 
 
 def build(config, live_server=False, dirty=False):
-    """
-    Perform a full site build.
-    """
+    """ Perform a full site build. """
+
     if not dirty:
         log.info("Cleaning site directory")
         utils.clean_directory(config['site_dir'])
@@ -204,13 +216,6 @@ def build(config, live_server=False, dirty=False):
 
 
 def site_directory_contains_stale_files(site_directory):
-    """
-    Check if the site directory contains stale files from a previous build.
-    Right now the check returns true if the directory is not empty.
-    A more sophisticated approach should be found to trigger only if there are
-    files that won't be overwritten anyway.
-    """
-    if os.path.exists(site_directory):
-        if os.listdir(site_directory):
-            return True
-    return False
+    """ Check if the site directory contains stale files from a previous build. """
+
+    return True if os.path.exists(site_directory) and os.listdir(site_directory) else False