diff --git a/middleman-core/lib/middleman-core.rb b/middleman-core/lib/middleman-core.rb
index 6666961b..8a145506 100755
--- a/middleman-core/lib/middleman-core.rb
+++ b/middleman-core/lib/middleman-core.rb
@@ -22,8 +22,8 @@ require "middleman-core/vendor/hooks-0.2.0/lib/hooks"
 module Middleman
   WINDOWS = !!(RUBY_PLATFORM =~ /(mingw|bccwin|wince|mswin32)/i) unless const_defined?(:WINDOWS)
   JRUBY   = !!(RbConfig::CONFIG["RUBY_INSTALL_NAME"] =~ /^jruby/i) unless const_defined?(:JRUBY)
-  DARWIN  = RbConfig::CONFIG['target_os'] =~ /darwin/i
-  LINUX   = RbConfig::CONFIG['target_os'] =~ /linux/i
+  DARWIN  = RbConfig::CONFIG['target_os'] =~ /darwin/i unless const_defined?(:DARWIN)
+  LINUX   = RbConfig::CONFIG['target_os'] =~ /linux/i unless const_defined?(:LINUX)
   
   # Auto-load modules on-demand
   autoload :Base,           "middleman-core/base"
diff --git a/middleman-core/lib/middleman-core/cli/build.rb b/middleman-core/lib/middleman-core/cli/build.rb
index 1cc766bc..d2b19b6a 100644
--- a/middleman-core/lib/middleman-core/cli/build.rb
+++ b/middleman-core/lib/middleman-core/cli/build.rb
@@ -102,6 +102,7 @@ module Middleman::Cli
       begin
         destination, request_path = self.class.shared_instance.reroute_builder(destination, request_path)
 
+        # $stderr.puts request_path
         response = self.class.shared_rack.get(request_path.gsub(/\s/, "%20"))
 
         create_file(destination, response.body, config)
@@ -189,6 +190,15 @@ module Middleman::Cli
     def execute!
       # Sort order, images, fonts, js/css and finally everything else.
       sort_order = %w(.png .jpeg .jpg .gif .bmp .svg .svgz .ico .woff .otf .ttf .eot .js .css)
+      
+      @app.sitemap.all_paths.select do |p|
+        File.extname(p) == ".css"
+      end.each do |p|
+        Middleman::Cli::Build.shared_rack.get("/" + p.gsub(/\s/, "%20"))
+      end
+      
+      # Double-check for compass sprites
+      @app.files.reload_path(File.join(@app.source_dir, @app.images_dir))
 
       # Sort paths to be built by the above order. This is primarily so Compass can
       # find files in the build folder when it needs to generate sprites for the
diff --git a/middleman-more/features/compass-sprites.feature b/middleman-more/features/compass-sprites.feature
new file mode 100644
index 00000000..e4c060a6
--- /dev/null
+++ b/middleman-more/features/compass-sprites.feature
@@ -0,0 +1,4 @@
+Feature: Compass sprites should be generated on build and copied
+  Scenario: Building a clean site with sprites
+    Given a successfully built app at "compass-sprites-app"
+    Then the output should contain "images/icon-"
\ No newline at end of file
diff --git a/middleman-more/fixtures/compass-sprites-app/config.rb b/middleman-more/fixtures/compass-sprites-app/config.rb
new file mode 100644
index 00000000..e69de29b
diff --git a/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_down.png b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_down.png
new file mode 100755
index 00000000..2c4e2793
Binary files /dev/null and b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_down.png differ
diff --git a/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_left.png b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_left.png
new file mode 100755
index 00000000..5dc69678
Binary files /dev/null and b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_left.png differ
diff --git a/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_right.png b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_right.png
new file mode 100755
index 00000000..b1a18192
Binary files /dev/null and b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_right.png differ
diff --git a/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_up.png b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_up.png
new file mode 100755
index 00000000..1ebb1932
Binary files /dev/null and b/middleman-more/fixtures/compass-sprites-app/source/images/icon/arrow_up.png differ
diff --git a/middleman-more/fixtures/compass-sprites-app/source/stylesheets/site.css.scss b/middleman-more/fixtures/compass-sprites-app/source/stylesheets/site.css.scss
new file mode 100644
index 00000000..25a6f535
--- /dev/null
+++ b/middleman-more/fixtures/compass-sprites-app/source/stylesheets/site.css.scss
@@ -0,0 +1,3 @@
+@import "compass";
+@import "icon/*.png";
+@include all-icon-sprites;
\ No newline at end of file