diff --git a/app/views/admin/schedules/_day_tab.html.haml b/app/views/admin/schedules/_day_tab.html.haml
index 4fdf7256..b88d8e6e 100644
--- a/app/views/admin/schedules/_day_tab.html.haml
+++ b/app/views/admin/schedules/_day_tab.html.haml
@@ -9,7 +9,7 @@
   - @rooms.each do |room|
     - non_schedulable = room.tracks.self_organized.confirmed.any? do |track|
       - !track.schedules.include?(@schedule) && (track.start_date..track.end_date).include?(date)
-    .col-xs-6{ class: ('non_schedulable' if non_schedulable) + " col-md-#{col_size}" }
+    .col-xs-6{ class: "#{('non_schedulable' if non_schedulable)} col-md-#{col_size}" }
       .room-name
         - room_date_event_schedules = date_event_schedules.select{ |e| e.room == room }
         = room.name