diff --git a/group_vars/web b/group_vars/web
index 3c11865..9625baf 100644
--- a/group_vars/web
+++ b/group_vars/web
@@ -8,4 +8,7 @@ webserver: nginx
 extra_fail2ban_filters:
   - nginx
 
+# root prefix for all web servers
+web_root_prefix: /var/www
+
 # vim: set ts=2 sw=2:
diff --git a/roles/caddy/defaults/main.yml b/roles/caddy/defaults/main.yml
index 3d9f6ff..99fe21d 100644
--- a/roles/caddy/defaults/main.yml
+++ b/roles/caddy/defaults/main.yml
@@ -2,7 +2,7 @@
 # file: roles/caddy/defaults/main.yml
 
 # parent directory of vhost document roots
-caddy_root_prefix: /var/www
+caddy_root_prefix: "{{ web_root_prefix }}"
 
 # Email address to use for the ACME account managing the site's certificates.
 # Not sure what Caddy does if this doesn't exist.
diff --git a/roles/nginx/defaults/main.yml b/roles/nginx/defaults/main.yml
index 84c2dbc..06a22a0 100644
--- a/roles/nginx/defaults/main.yml
+++ b/roles/nginx/defaults/main.yml
@@ -5,7 +5,7 @@
 nginx_confd_path: /etc/nginx/conf.d
 
 # parent directory of vhost roots
-nginx_root_prefix: /var/www
+nginx_root_prefix: "{{ web_root_prefix }}"
 
 # 1 hour timeout
 nginx_ssl_session_timeout: 1h