diff --git a/templates/vhost/vhost_header.erb b/templates/vhost/vhost_header.erb
index cf26c3f..ab94a74 100644
--- a/templates/vhost/vhost_header.erb
+++ b/templates/vhost/vhost_header.erb
@@ -128,7 +128,7 @@ server {
 <% end -%>
 <% if @add_header -%>
   <%- @add_header.keys.sort.each do |key| -%>
-  add_header              <%= key %> <%= @add_header[key] %>;
+  add_header              '<%= key %>' '<%= @add_header[key] %>';
   <%- end -%>
 <% end -%>
 <% if @maintenance -%>
diff --git a/templates/vhost/vhost_ssl_header.erb b/templates/vhost/vhost_ssl_header.erb
index 6e1367f..ca89577 100644
--- a/templates/vhost/vhost_ssl_header.erb
+++ b/templates/vhost/vhost_ssl_header.erb
@@ -131,6 +131,6 @@ server {
 <% end -%>
 <% if @add_header -%>
   <%- @add_header.keys.sort.each do |key| -%>
-  add_header              <%= key %> <%= @add_header[key] %>;
+  add_header              '<%= key %>' '<%= @add_header[key] %>';
   <%- end -%>
 <% end -%>