diff --git a/lib/singed/railtie.rb b/lib/singed/railtie.rb
index 2c7122b..5fae6e0 100644
--- a/lib/singed/railtie.rb
+++ b/lib/singed/railtie.rb
@@ -14,7 +14,7 @@ class Railtie < Rails::Railtie
     end
 
     def self.init!
-      Singed.output_directory = Rails.root.join("tmp/speedscope")
+      Singed.output_directory ||= Rails.root.join("tmp/speedscope")
       Singed.backtrace_cleaner = Rails.backtrace_cleaner
     end
   end